By the time Spike heard the knock on the door, he was already on his feet.

Truth be told, he’d been watching out of the window, tapping his claws impatiently as he waited for her to arrive. The very moment she came into sight, he’d quickly ducked out of view, then silently counted out the seconds until she reached for the doorknocker. The instant those twin thud-thuds sounded through the library, he was sliding across the floor, a wide grin slapped over his face.

The door knob turned easily in his hand, and the door clicked open without a fuss. “Rarity!” he said, swinging it wide. “Hey!”

“Hello, Spike,” Rarity said. She smiled at him, her thick, dark-red lips curling warmly. “How wonderful to see you. How have you been?”

“Oh, great,” he said. “Just great.” She was staring up at him, some part of him registered. It wasn’t the first time he’d noticed that, and it certainly wouldn’t be the last. His last growth spurt—sometime before his seventeenth birthday last year—had put him at a good two inches taller than Twilight and nearly a full ten inches taller than Rarity. He wasn’t entirely sure what to think about that, especially considering she’d been bigger than him for most of his life.

Then again...that wasn’t to say that she wasn’t still big in other places. His bird's’ eye view of her gave him a perfect angle of her big...round…

Spike swallowed. Oh, Celestia, how did she even manage to fit those breasts into a neckline that tight? Rarity had always been a well-endowed mare, a fact which he’d manage to recognize even as a preteen with barely a libido to speak of. Just something about the way her bust swayed was hypnotic, especially given the way any kind of fabric clung so perfectly to the smooth, rounded curves of her—

“So,” Rarity said. “I presume Twilight is downstairs in the lab?”

Spike’s gaze jerked upward. He met Rarity’s eyes guiltily, and forced an innocent grin onto his face. “Oh, yeah,” he said, doing his best to pretend that his pants weren’t suddenly three sizes too tight. His crotch stirred at the sight of her full, succulent mouth, at her cute, dimpled cheeks, and he bit down on his lower lip. Hard. “She’s, uh, just waiting for us. Why don’t you come on in?”

He stepped aside, and gestured inward. Rarity giggled and swept her way in, holding her hands delicately to her waist.

“Such a gentledrake,” she murmured, and shot him a grin. Spike lingered for a moment as she made her way past, unable to keep his wandering eyes from darting down toward her well-stuffed rear. If Rarity’s bosom was impressive, she was even more so beneath the waist. The way her ass filled out her tight pants was absolutely incredible; it was impossible to ignore the way she jiggled and bounced, just ever so slightly, with each alluring sway of her hips—

“Spike?” he heard Rarity call. “Could you, perhaps, remind me where the basement door is?”

He very nearly jumped out of his scales. “Oh! Right, sorry!”

He rushed up to find that she was already standing in front of it. He grinned sheepishly down at her and reached to fiddle with the door knob; she smirked back up at him, a knowing, mischievous note in her smile. Spike gulped, then quickly swung the door open. This time, he went first.

“Twilight?” he called, the wooden steps creaking beneath his weight. “Rarity’s here.”

“Rarity!” Twilight whirled to face them, a big grin on her face. She held a clipboard in her hands, and a lab coat was slung hastily over her shoulders. Behind her, a row of brightly colored beakers bubbled happily. Even as Rarity touched down into the basement behind Spike, Twilight had already taken her hand to shake it, all the while babbling excitedly.

“—so glad you could make it; this really was a very time-sensitive test, and I think you’ll—“

“It’s good to see you too, Twilight,” Rarity said. She smiled up at her and winked. “I take it you’re excited about our little experiment today?”

“Oh, yes.” Twilight ushered her over to the side of the room, where a simple chair was waiting. “Here, have a seat.”

“Thank you, dear,” Rarity said. She looked all around the room, her lips pursed. All around them, Twilight’s basement laboratory was stuffed with strange and exquisite machines, beakers, and books. “Is the item you wished to investigate, ah, here?”

“Oh, yes.” Twilight’s horn glimmered, and a dark, clay-wrought sculpture floated down off of a nearby table. Rarity nodded, leaning slightly forward in her chair to inspect it. “It was located in a dig near Bronkostan, and my contacts at Canterlot U are very eager to see how it operates.”

“What is it, exactly?” Rarity asked. She peered at it. “I quite like the patterning.”

“From the research we’ve done,” Twilight said, “we’re fairly certain that it’s the ‘Arkh de Gargantua,’ a holy relic of the ancient Herdsians. Some cursory investigations have revealed the expected enchantments placed upon it, each representing virility, plenty, and strength.”

“Virility and strength?” Rarity repeated, cocking her head. “That sounds...interesting.”

Twilight’s head bobbed happily. “Yup! We suspect that the artifact was used to ‘create’ their Empresses. Stories tell of Herdsian rules who towered above their subjects. They were goddesses to their people, and symbols of power and empowered sexuality.” She blushed a bit at that last word, but powered forward. “While I’m fairly certain that most of them are exaggerated, testing this artifact might give us some insight into semi-permanent physical alteration spells.”

“And you’d like to test it on me?” Rarity said. She raised a hand as if to touch it, and held it there, looking almost hesitant. “Well. I can’t say that I haven’t always dreamed of being a touch taller. Or a mite more...bountiful.” Spike, who’d been leaning against the desk behind Twilight, caught her smirking at him and flushed, glancing away. Rarity stifled a giggle. “All in all, this venture sounds positively intriguing! I’m in.”

“Great,” Twilight said. “So, before we start, I’ll just need your height.”

“Five feet and three inches,” Rarity said. “And one-half.”

“Okay, then,” Twilight said. “I’ll just need you to actuate yourself to the artifact, and then we can begin.”

“And how exactly might I do that?”

“Just place your hand on the circular panel in the center,” Twilight said. Rarity bit her lip, and hovered her hand over it. Twilight’s deep purple aura shimmered around the object, casting it into an eerie glow. “It’ll take a few seconds to calibrate, and then we should be good to go.”

Rarity nodded, and placed her hand on the device. At first, she felt nothing. And then…

“Hm,” she said, frowning at it. “Nothing.”

“I haven’t turned it on yet,” Twilight snickered. “But that should be fine. Now I just need to bring it over here and turn it on.”

Rarity waited patiently as Twilight set the artifact back down on the desk and began to fiddle with it. Her feet, dangling slightly in the air, tapped against the legs of the stool Twilight had sat her on.

What would it be like to be taller? she wondered. Not quite so much taller, surely...but just a little bit? She was certainly no “small” mare, not where it counted, at least, but when it came to height… A few months ago, she’d been eye-to-eye with Twilight, a rather short mare herself. And then had come Twilight’s ascension, and Rarity had found herself staring at her friend’s collarbone more often than not.

Not too much, surely. Just a few inches. Her lip curled into a smile. It would be nice to speak with Twilight eye-to-eye again, wouldn’t it? And perhaps just glance the teensiest bit downward to greet Rainbow Dash, or even Applejack. A heated thrill tingled up her spine.

“And...done.” Something clicked, and Twilight stepped away from the artifact. A deep blue light began to flicker and play across the patterns covering the artifact, and a low, resonating hum filled the room. “We should be starting now.”

Rarity nodded, and closed her eyes. Her fingers curled tightly around the edge of the school. She tried to cast her consciousness into every corner of her body, feeling for any sort of change. What would it feel like when she found it? Would she even notice?

But...there! She bit down on her lip, flurries of anticipation tightening her chest. It may have been just her imagination, but she thought she could feel a soft warmth building in her stomach, a golden, tingling pulse that spread heat through her entire body. A short grunt escaped her, and she felt her hairs standing on end. Something tightened and stirred at her crotch, her top growing tighter against her bra as her nipples stiffened with excitement.

And then...it was over. Rarity held onto the stool for a few seconds more, counting to ten before exhaling and letting go. She opened her eyes, first the left, and then the right, and saw...nothing. No apparent change.

The device had stopped glowing. Twilight was eyeing her, and Spike was frowning. Rarity furrowed her brow, frowning as well.

“Well?” Twilight said. “How do you feel?” A pen clicked, her clipboard pulling up into position.

“There was…” Rarity lifted her right hand and eyed it oddly. A twitch of her fingers sent the tendons in her wrists flexing, twisting. Funny, really, how a sensation like that could make a mare notice just how her body fit together. “There was something, I’m sure. But I don’t feel any different.”

“You don’t look any different, either,” Spike piped up. Rarity’s gaze flickered toward him. Was that...disappointment, she’d heard? Before she could process that further, Twilight spoke up.

“Well,” she said, “that remains to be seen. This was only the first test, after all.” She nodded toward a series of lines and markings pencilled onto the wall beside Rarity’s stool. “Shall we take your height and see if there’s been any change?”

Rarity nodded. Gracefully, making sure not to stumble, she swept off of the stool and onto the floor. She stood patiently with her back against the wall, making sure to keep her spine straight as Twilight measured her height from the top of her head.

Twilight gave a strangled sound of excitement. Rarity jumped, then let out a ladylike “oof” when her head collided with the pen Twilight had been pressing down against her.

“What is it, Twilight?” Rarity said, wincing slightly. “Did it—did it work?”

Twilight snatched the pen back with a wide-cheeked grin. “It did!” she said, floating her clipboard over with a gesture. Scribbling furiously, she said, “Unless you can remember the last time you were five feet and four inches.”

Rarity’s heart skipped a beat. “I—no!” she said. That thrill of excitement was returning, leaving flutters in her chest and stomach. “I haven’t grown since middle school! I know my measurements very precisely.”

“Well,” Twilight said, her grin stretching from ear to ear. “You’d better take them again!” She turned to Spike, who was holding a clipboard of his own with wide eyes. “Spike! I need you to write down some measurements for me. We’re going to need to have a very thorough documentation of any changes in Rarity’s physiology.”

“I—oh!” Spike’s eyes widened, and his cheeks reddened when he saw Twilight floating over a strip of measuring tape over toward the two of them. His blush only deepened when Twilight wrapped it around Rarity’s waist, then her arms, though he made sure to note down the numbers she gave him with crisp precision all the same.

By the time Twilight made it to Rarity’s thigh, Rarity’s whole body was positively humming with pleasure. She couldn’t quite put a finger on it, but it was a sort of warm, heady buzz that filled her head with dreams of success. She was taller. She was—well, bigger! She stifled a soft moan as the back of Twilight’s hand brushed against her crotch, wondering if her breasts did feel a bit heavier after all…

Twilight froze mid-crouch. She turned to face Rarity’s stuffed, bulging crotch and stiffened. “Um,” she said. “Rarity? Is there something you, er, haven’t told me?”

Rarity blinked—and then glanced down at her groin. Just around Twilight’s eye-level was a long, thick bulge that almost resembled a cotton tube thrust into her pants. She drew in a sharp breath, and felt the muscles at her crotch tighten. Just as she did so, the bulge flexed, a hot, heavy muscle that she was sure she’d never felt before.

“Oh,” Rarity said. “That’s new.”

At the edge of her vision, Rarity could see Spike gaping. Twilight’s astonishment, meanwhile, made itself perfectly obvious. However, Rarity felt not a drop of embarrassment or shame; instead, she felt a small sense of satisfaction. It was right, some part of her told her, that they should be staring at her with such awe. It was right, she knew, that she take pride in her body, revel in it, even, than deny it.

So instead of shrieking, tensing, or fainting, Rarity simply frowned, and poked at her bulging crotch with her pointer finger. Her fingernail sank a good bit into the plump, tented bulge, and she groaned at the sudden surge of pleasure that followed. Goodness, but that was unexpected.

Twilight, meanwhile, was blushing furiously. Spike may as well have gone into a state of catatonic shock; his eyes were wide, his mouth hanging open, his cheeks redder than a ripe tomato.

“Okay,” Twilight said. “This is...unexpected. But…” She coughed into her fist, averting her eyes from Rarity’s. “I suppose that for this to be a completely clinical trial, we really should take note of all alterations following the artifact’s effect.” She levitated the measuring tape up into the air and grimaced.

“Oh, please do,” Rarity said. “I’m as curious as you are.” Her crotch gave another involuntary flex, and she groaned softly, a soft vein of pleasure winding around her groin.

Twilight nodded. “Spike?” she said, gathering her lab coat around her chest. “If you would look away for a moment?”

“Whatever for?” Rarity asked.

Twilight made a strangled sort of sound halfway between a groan and a snort. “I—you’re a lady, Rarity. It just wouldn’t be proper.”

“Nonsense,” Rarity said cheerily. She was a beautiful mare, and beautiful mares deserved to be admired. It was something she’d known all her life, but only now was she realizing the utter truth of it. “It would do me no harm.”

She glanced toward him. Spike refused to meet her eyes, but from the bright red blush on his cheeks, and the occasional darting of his gaze toward her… Rarity’s lip curled upward. Oh, he was so cute when he was interested.

Twilight, thankfully, didn’t make a show of removing Rarity’s pants. She simply slipped them off, revealing the white laced panties that Rarity had lovingly pulled on that morning. Only now, they weren’t so white—a dark, damp splotch of wetness had spread across their surface, and the material had been stretched so tight across the expanse of her new endowment that a field of dark, mottled black was almost clearly visible beneath it.

Rarity exhaled slowly. For it was an endowment—a large, heavy stallionhood that made her panties bulge with definition. A pair of fat, black orbs, each half the size of her fist, rounded out the laced silk surface; atop them, a long, thick shaft lay draped over the top, its wide flare stuffing her panties full and smearing the fabric with a dark, musky liquid.

Rarity sighed softly as Twilight went about measuring her new appendage. Perhaps she wasn’t quite brave enough to remove Rarity’s clothes entirely, but Rarity’s endowment was large enough that Twilight could measure it quite easily through the fabric, even flaccid. The sensation of Twilight’s slender fingers across her stallionhood, though, made Rarity’s groin flex and stir with excitement; before she knew it, her member was swelling in length, stiffening and growing in size even as the fabric of her panties groaned and stretched around it.

When she’d grown to her full length, Rarity made a delighted little noise. “Oh, my,” she said. “Twilight, it’s gotten so much bigger! Could you possibly measure it again for me, please?”

Twilight, who’d been preoccupied measuring the radius of Rarity’s balls, eyed the large shaft with some trepidation. She swallowed, and held the tape measure up to measure it properly.

“Seven and a half inches,” she said. “From tip to base.”

“Is that large?” Rarity asked. Twilight and Spike exchanged a look.

“Statistically speaking?” Twilight said. “It’s about average for a stallion. Maybe a bit on the small side, actually.”

Rarity wilted. “Oh,” she said. She could recall, she realized, eyeing a stallion here or there in the marketplace, or strolling down a Canterlot boulevard, their pant legs looking quite stuffed with a delicious bulge of meat. She had thought she’d seemed respectable at first, but really, that was just from the surprise of seeing something where there had once been nothing.

“How large are you, Spike?” she asked casually. The Rarity of last night would never have dared asked such a question—not without sufficient alcohol and a pleasant date beforehand—but today, she could feel her spirit surging with a new boldness. Plus, she was curious.

If Spike’s cheeks had been burning before, they were a blazing inferno, now. “I—uh—“

“Thirteen inches,” Twilight blurted.

Spike’s eyes bulged. “Twilight!”

“I—I’m sorry!” Twilight said. She cowered, stepping away from Rarity’s tented, musky crotch. “I didn’t mean anything by it. It’s just—I’ve been interested in draconic anatomy ever since we started living together, and there’s just no research on it at all! I thought I might just...take some measurements.” A sickly blush crossed the bridge of her nose. “I didn’t mean anything by it, honest!”

“Of course you didn’t, Twilight,” Rarity said, not unkindly. Her rich, elegant voice cut between the other two like a knife through butter, and both Twilight and Spike turned to look at her with the wide eyes of foals interrupted in the middle of a mischief. Rarity’s nose twitched, and she thought she smelled, if only for a second, the familiar scent of a mare’s arousal wafting from Twilight’s direction. Interesting, she noted bemusedly, eyeing Spike from the side.

And yet… Her gaze turned to her own crotch again. A tent that had once seemed grossly oversized now seemed incredibly small, even pathetic. Rarity frowned in disappointment. “Smaller than average,” she said under her breath. “Thirteen inches.”

A few seconds passed before she looked up again. Twilight had pulled herself fully to her feet, and once more Rarity was struck by just how tall she was now. Even a five-foot-six Rarity was still a shrimp compared to the six-foot-tall beauty of an alicorn. Twilight’s breasts were fuller, her arms just a bit more defined, than even Rarity had ever hoped to aspire toward. And Spike was another two inches taller than that...and yet, from the way he’d looked when the experiment had begun, even he was interested in seeing a larger, more gifted Rarity.

“Twilight,” Rarity said, “do you believe we’ll be able to continue the experiment?”

“Huh? Oh.” Twilight stepped back, and crossed her hands over her chest. “Um. Well. I wouldn’t want to put you through any changes that you might feel uncomfortable with. So if you’d like to stop now…”

“Oh, no, no, no!” Rarity said. “I’m actually quite interested in seeing where this goes.” She flashed a white smile in Twilight’s direction. “This morning has already turned out quite a bit more exciting than I expected it to be. I would hate to cut off your research now, especially if you’re gathering so much good data.”

“Right. Of course.” Twilight turned back to her clipboard, and she nodded. “We are gaining an awful lot, so I certainly wouldn’t mind continuing. Just…”

Rarity waited. “What, dear?” she finally asked.

Twilight blushed. “Put your pants back on?”

Rarity laughed, and did as she was told.

Small tingles of excitement danced up and down Rarity’s spine as she readied herself for the next test, pressing her shoulder blades firmly against the laboratory wall. There would be no stool for her now; she wanted to see herself grow. She watched Twilight setting up the artifact with no small amount of trepidation; as little as she’d grown the first time, she somehow had faith that this test would leave a much more...noticeable difference.

A coy smile crossed her face when Twilight was finally finished. “Ready when you are, dear,” Rarity said. Twilight nodded, and turned to switch the device on.

Oh, yes! Rarity’s ears perked up in delight as she felt the familiar warmth growing to encompass her body again. She gave a soft moan, feeling her nipples stiffen against her bra as golden veins of energy suffused her limbs. This was exactly what she’d wanted.

She could already feel it. It’d been too small for her to notice consciously the first time, but now she was prepared. She recognized the sensation instantly: a pressure at her crotch, a tightness about her waist, a steady stre-e-e-tch in her limbs. Rarity stretched, groaning with the pleasure as the growth overtook her, flinging out her arms even further than she had just moments ago. She could feel her spine creaking, her chest filling out, her crotch bulging larger with size and definition as she inched up in the air, bit by bit.

Now this was the size she’d been waiting for. “Mm,” Rarity purred, her body twisting in delight as she felt her form surge with energy. Already, she could see that the world looked different from up here—why, she’d never spotted that freckle on the bridge of Twilight’s nose. Looking across or down was so much better than looking up. She spotted Spike staring at her with awe, and smiled; her hands clenched into fists, and she grunted softly as she resisted the urge to explore and fondle her larger, growing body.

By the time she finished, Rarity didn’t just feel slightly different. She felt stronger. More powerful. Twilight walked up to her, clipboard in hand, and Rarity realized, to her shock, that she was now barely a smidgen shorter than Twilight! The difference couldn’t be more than a few inches—how much larger had she grown, really?

“Five feet, ten inches,” Twilight announced. She pulled the measuring tape away from the wall and made another few notes in her clipboard. “Gosh. That’s an entire six inches!” She blinked across (not down, Rarity thought with a thrill) at Rarity and said, “How do you feel?”

Rarity smiled. “Darling,” she purred, stretching her arms above her head. Her spine arched like a cat’s, pushing her ample chest forward. That had certainly grown as well; if she’d been well-rounded there before, it now looked like two oversized melons had been simply stuffed down her front, her round, firm cleavage filling out her top until it looked borderline obscene. She glanced aside to smile at Spike, releasing her stretch by bending forward—which just happened to reveal a good four inches of creamy white cleavage as well. “I feel simply wonderful. Don’t tell me we’re going to stop here.”

“Well…” Twilight took a step back and eyed her up and down. She was frowning; evidently, she wasn’t quite as prepared for a taller, bustier Rarity as she’d thought. Rarity also noted that Twilight was carefully keeping her eyes above Rarity’s waistline; with a silent giggle, Rarity felt her new stallionhood flex and throb in her panties, her balls already feeling the tension of being stuffed into a pair of pants too small to contain them. Her pants had been designed to hold a petite, dainty mare...but Rarity was growing up to by anything but.

Twilight pursed her lips. “I think we should probably try to keep going. Just a little bit. One or two more tests couldn’t hurt.”

“Oh, thank you, Twilight.” Rarity gave her an earnest smile, and hugged her wider hips. Her fingers sank a bit into her larger, plush ass, which had begun to push the hem of her too-short pants down, even as the bottoms hung just over her ankles.

As Twilight began to set up for the next test, Rarity couldn’t help but add, “I do wonder if I’ll grow taller than you in the next test, Twilight? Or perhaps—“ her eyes flicked to the side, and she licked her lips lasciviously—“even our big, hunky dragon?”

Now that got a reaction from Spike. He choked on something—his tongue, perhaps?—and quickly twisted off to the side. Twilight did her best to keep her gaze fixed on the artifact, but a soft, amused smile tinged Rarity’s face with mirth.

Rarity was more than ready for the next test to go off. It struck her like a golden beam of warm, bubbling light—and then, once more, she felt herself begin to expand. She moaned, her supple lips parting as her head inched up into the air. Her top tightened around her bust, her breasts fast becoming far too much to hold. Pants which had once covered her down to her shoes pushed above her ankles, then up to just below her knees. A sense of power, of strength, of unbridled, swelling size filled her, her muscles flexing, tightening, bulging with newfound definition as Rarity’s body ascended to a grander state.

The sensation of it was nearly too much for her. Soft coos of pleasure and satisfaction slipped past her lips as she passed six feet and continued upward. Small rips and tears appeared across her rapidly shrinking pants, her thick, lascivious thighs pushing their way through. Her hand slipped across the bulge at her crotch, which had already doubled in size from its original girth. She felt the long, snaking shape of her new shaft pressing against her tearing, creaking pants; as new moans sprang from her throat, low and rumbling and throaty with sex, she began to stroke her length, at first with hesitation, and then with gusto, pulling her long, slender fingers up and down her member as her balls grew fatter and heavier with seed.

The musk—oh the musk! The air all around her stank of size, of sweat, of sex. Rarity let out a throaty growl as a long rip emerged down the front of her top, oodles of abundant titflesh poking through. A seam cracked across the middle of her thigh, letting the fat blackness of her medial ring show through. Up she went, widening, growing in size and sensuality, as she filled out her clothes far beyond what a much smaller mare could.

Her overstuffed, torn clothing left absolutely nothing to the imagination. Rarity shivered with delight, her hands pulling up over her thighs as she felt her crotch tightening with further arousal. Her fingers traced across the bulge in her straining pants that covered her shaft, and she gasped with pleasure. She looked down, gazing past the massive shelf of titflesh jutting out from her chest, and eyed the fat bulge throbbing along her thigh with a lick of her lips. She looked unbelievably delicious.

Her gaze shifted up. And the room! It seemed so much smaller than it had before—or she was simply bigger. The thought sent shivers of excitement surging up and down her spine, her own enthusiasm causing her pants to tear a little further around the girth of her thick, flaring horsecock. Rarity groaned lustily, every nerve on her body suddenly seeming that much more alive.

Twilight opened her mouth to speak, but Rarity barely paid any mind to her. Her eyes latched onto Spike. Goodness, was he shorter than her now? Just that morning he’d been the strong, masculine drake—and yet now even he was small compared to her. Almost lazily, she lifted her hand and crooked a finger, beckoning him over.

He took a step forward on sheer instinct, his reptilian reflexes pushing him to submit to the larger female. Rarity’s eyelashes fluttered, and her voice cooed, “Spikey-wikey, won’t you come over here for a moment? I’d love to compare.”

Spike swallowed, and stepped forward again. As he approached Rarity, she noticed that his hands were trembling. Not in fear, she could tell by the look in his eyes, but in excitement. It was amusing, she reflected with a quirk of her lips, how she felt no simple butterflies bouncing about in her stomach, but rather a total, searing lust for more.

She looked down on him—down on him! Idly, she remembered that he’d been six-foot-two the time he’d been measured last. Why, he only came up to the bridge of her nose now! She estimated her own height at six-foot-five—even, she thought with a stifled giggle, six and a half feet! An entire foot taller! What a mare she was becoming!

Aloud, she merely hummed thoughtfully. Certainly, she was taller than Twilight now, but it was Spike—her longtime pursuer, and till today, one of the more masculine “stallions” she’d known—that she was interested in. One long, manicured fingernail traced along the contours of his bicep, her finger curling around his muscle.

Beneath her gaze, Spike fidgeted anxiously. Not out of fear—gosh, no. But Rarity’s arms were just a bit thicker than his, now, her biceps swelling intimidatingly as she drew her finger down across his wrist. And her breasts—so big and full, large and plump enough to nearly brush against his chest at this distance. He was reminded of his own chest, his unexercised pecs flat, unnoticeable. Rarity, though, was all but guaranteed to be noticed now, no matter the time or the place.

Her nipples were erect and quivering with obvious arousal, her bra and shirt struggling to hold on. Spike caught a generous eyeful of her cleavage; it was obvious that the top buttons of her shirt were straining to keep together around the dozen-plus pounds of cleavage stuffing them full. He swallowed, unable to keep himself from undressing her beyond what her growth had already done for him; his cock flexed in his pants, a spurt of pre painting his underwear dark.

Her hands stopped at his waist, then curved around his thigh. Spike’s legs tensed as both of their gazes went to his crotch. His groin was heavily tented, his erection throbbing with obvious arousal as a damp spot spread across the fabric of his pants. Rarity’s bulge, though… He gulped again. Hers was much larger.

A bulge nearly as thick as his wrist snaked down along her thigh, ending just a few inches short of the knee. Rarity sighed happily, her body quivering with delight as Spike’s hand hesitantly brushed against her bulge. A stream of clear pre steadily dripped down out of her pant leg, pooling on the floor in a growing puddle of arousal. She met his eye, grinned.

“My,” Rarity murmured, looking down on him. “Not so large a drake, are you, dear Spikey-wikey?”

Spike blushed. He bit his lip, unsure of how to respond. Instincts fought their way up inside of him: a demand to submit, an urge to be railed, rutted like breeding stock. His body recognized a female alpha dragon standing before him, looming above him. Rarity was all but purring with lust, her output already enough to put any stallion to shame. He felt a mighty, overpowering urge to bow down, to please her—and yet his ego warred with his lusts, his masculine sense of self pushing, straining against this new reality.

Rarity laughed softly at the pink color on his cheeks. “I’m only joking, Spike dear,” she said, shooting him a wink. “You’re a big, tough dragon.” She gave his thigh a squeeze, and Spike sucked in a breath. “I just happen to be a bigger mare.”

Spike found himself salivating, staring at the fat outline of her balls at her crotch. How much seed must those contain—much cum must be churning, sloshing within their orblike depths? Rarity stifled another moan, her muscles tensing as another lurch of her cock sent precum shooting down out onto the floor.

Her hand lingered on his cute, chubby rear for a moment, pausing as if pondering claiming it for her own. Spike could feel his arousal stirring, his head bowing reflexively as Rarity’s nails tightened around his wide hips—

Twilight coughed. “Am I interrupting something?”

“Not at all,” Rarity said, not missing a beat. She smirked down at Spike, and caressed his cheek lightly. He shivered, his long, reptilian tongue darting out past his lips. “I’m just...appreciating the new view.”

“I can tell,” Twilight said. There was a tremor in her voice, but an undeniable interest as well. “In any case, we’re still here for the science, right? The data.”

“Of course, Twilight,” Rarity purred. She brushed her crotch with a hand, and stifled a moan of delight at the wonderful throb of ecstasy that echoed through her body. Her palm came away wet and sticky, and she eyed it, yearning to lick it clean. “But science can be fun, can’t it?”

“Oh, yes,” Twilight said. “But you’re rather large as it is—once I’ve taken your next measurement or two, we should probably stop.” She chuckled weakly. “Wouldn’t want you getting stuck down here, right?”

Rarity’s smile became catlike. “What a shame that would be,” she said. To have this huge, beautiful body hidden from the world—tragic. She flexed an arm, and sighed when she saw her magnificent breasts bouncing against her chest. Then again...she could always get even bigger.

Twilight didn’t seem to notice her hidden meaning. “Great,” she said. “Spike, if you wouldn’t mind?”

“Oh! Right!” Spike spun around and made to walk away. Just as he did, Rarity caught a glimpse of his wide, plump rear. It filled out his jeans so nicely, his chubby cheeks straining against the fabric of his pants, that she couldn’t resist giving it a hard smack! Spike jumped, muffling a yelp, as his thick rump bounced and jiggled like jello. Rarity giggled with delight, but quieted herself when Twilight’s gaze turned back to her.

“Okay, then,” Twilight said. “Next test, begin.”

Rarity’s whole body tensed up at her words. She was ready for more—more size, more power, most lust. Her leg was absolutely drenched in precum, and rivulets of pleasure tittered through her system with each throb of her shaft. The instant the beam of magical light hit her, Rarity moaned, every muscle in her body flexing all at once.

Her cock flexed too—and with that, she felt a pressure building in her loins such as she’d never felt before. She groaned, her voice low and rich, as her head inched up higher into the air, taller than ever before, her breasts, ass, and muscles filling out as she grew to tower above the others. Her clothes shredded and ripped around her enormous body, the pressure growing to incredible levels until there was no way to hold back any further—

Rarity gasped as she came, her chest seizing up as her hips bucked forward into the air. Her enormous cock, now more than a foot and a half in length, lurched and bucked as it splurted heavy ropes of cum down her torn pant leg. Rarity moaned, her body gyrating in pleasure as cupfuls of jizz splattered all over the ground below her. Her pants continued to tear, the fabric ripping as her cock and thigh thickened considerably with her mounting height. Spike took a step back, his body swaying as he gaped at her incredible output.

Oh, there was so much cum. Rarity’s mouth hung open, rumbling moans echoing from her vocal chords as her fat, churning nuts put out more and more creamy white batter by the second. Was this what the goddess-empresses of Herdsia had felt: this power, this overwhelming virility? For a goddess she was becoming, even as her melon-sized nuts emptied cupfuls of thick, gooey spooge in a growing puddle beneath her.

The growth ended at last, leaving her noticeably larger than when it had started. Rarity wheezed, her oversized breasts heaving and smacking against her chest as she doubled over, unable to stop the tremors of pleasure vibrating through her body. She groaned lustily, squeezing both hands across the long, thick bulge of her cock and milking it for its last drops of seed.

When her eyes opened again, she noticed Spike and Twilight staring at her. Yet Rarity felt neither embarrassed nor ashamed of her orgasm or pleasure. Why should she? Another shiver of delight tingled up her spine. She was becoming a goddess, and it was beneath a goddess to ask for the forgiveness of her worshippers.

Rarity loomed over them both, now over seven feet tall and easily large enough to outweigh them both put together. Even the top of Spike’s head only reached her chin; Twilight’s ears, meanwhile, didn’t even brush the top of her shoulders. Rarity groaned softly, kneading her overly sensitive tits between a pair of arms that could no longer even hope to go all the way around; the plump, supple titflesh squished and jiggled at her touch, their contents warm and heavy.

“Oh, gosh.” Twilight’s voice was hesitant and quiet enough that Rarity had to blink twice before registering that the smaller mare had spoken. Rarity turned lazily toward her; Twilight had taken a step back, her cheeks flushed a bright red. “I didn’t think—I mean, I suspected that the artifact might have some impact on virility. But I didn’t think it would be this impactful. Oh, gosh, Rarity, I’m sorry.”

Rarity groaned softly. Apologies? Whatever for? She felt fantastic—better than ever, even. “Not to worry, Twilight,” she said. It took some effort to keep her voice from sounding sultry; between her new size and virility, it seemed almost as though Rarity’s body was egging her on, pushing her to sexualize every little motion and word. Her big body wanted sex, and each throb of dopamine in her brain tore her inhibitions down just a little bit further. “I’m...ooh, just fine.”

“Are you sure?” Twilight was still blushing madly, though she didn’t look quite discomfited as before. “I think we might want to stop here—it’s clear that the artifact is having an, um, adverse effect on you. I’ve got more than enough data points, and you’re behaving a bit...oddly.”

Rarity paused. Stop the experiment? And miss out on all of the size she had yet to gain? The old Rarity would have nodded, gone along with Twilight’s suggestions happily. The scientist knew best, after all.

But the new Rarity… The new Rarity was a growing, lusty goddess. How could a tiny, cute little mare like Twilight know what was best for her? As her inhibitions slowly broke down, Rarity was starting to view her growth not as a gift, but as long-since deserved. How many years had she spent as a weak shrimp of a filly? Only now was she finally being allowed to blossom into the prime, divine essence of power and femininity that she was becoming—would Twilight take that away from her?

“Darling,” Rarity said, her voice soothing, “I don’t think there’s any reason to stop now. Why, we’re pushing boundaries, dear. Surely a scientist like yourself knows the value of the cutting-edge.”

Twilight stammered out something unintelligible. Rarity smiled, and subtly pushed her chest out a little further. Her vast bust bounced lightly in the air, her enormous tits straining even tighter against the near-shredded strips of cloth binding them in place. By now, her shirt was long since a memory; the only part of it left was a thin red piece binding her voluminous tits to her chest. The only thing keeping them from welcoming her thick, drooling cock to their soft depths was the ripped remains of her pants—more shorts now, admittedly—clenching tight around her still-engorged member. Rarity cooed softly as she felt her melon-sized nuts filling up once again with fresh seed; already, she could feel the pressure between her thighs growing.

Twilight’s eyes darted up and down; evidently, even the Princess of Friendship was unable to keep herself from ogling her friend’s new stature. And yet…

She cleared her throat. “Rarity, I’m really not sure about this. Maybe we should stop for now and regroup later.”

“No!”

Both mares turned to stare at Spike. Spike’s eyes widened, as if surprised at the fact that he’d spoken at all—and then his cheeks reddened, turning a brighter, cherry shade of red.

“I mean…” Spike gulped visibly. “We wanted to get the most out of this that we could, right? It’d be silly to start over with another pony. And Rarity’s such a w-willing test subject. Maybe it wouldn’t hurt to go just a little—little bit further.”

Twilight stared at him. Rarity beamed. She could have hugged the little drake—or, better yet, bent him over and—

“Okay.” Twilight coughed. She blushed as well, just as Rarity was wondering where that little urge had come from. “We can...go a few more rounds, I suppose.” Her gaze snapped up to Rarity, and she raised a finger at her larger friend. “But not too big!”

“Of course,” Rarity purred. It was a struggle to keep her hands from either cuddling her voluminous, pillowy tits or stroking her magnificently huge cock, but she managed. Somehow. She had to be on her best behavior for Twilight if she wanted to get any bigger, after all. “Just enough to, ah, strengthen our results.”

Twilight’s cheeks looked like they were on fire. “Okay,” she mumbled. She turned back to the artifact with some reluctance; from the obvious stiffness of her wings, though, it was clear that she was having the same kind of reaction that Spike was. It was, Rarity reflected, a necessary outcome of her own size and virility. That, after all, was the clear result of sharing space with a goddess…

The moan passed Rarity’s lips before the beam of magic even hit her this time. She couldn’t help it—she was just so big, so huge, and about to get even more so. The thought excited her, made her blood sing, and she only grew more excited still as she felt her body begin to swell. Her muscles bulged; her bones creaked, lengthened; her nuts grew fatter, heavier as they pushed her thick, juicy thighs even further apart; and all the while, Spike’s eyes were firmly on her, irises dilating, cock throbbing as her own pillar of meat pulsed and twitched and drooled.

The ceiling didn’t seem so far away; the room, Rarity thought through half-lidded eyes, looked quite a bit more cramped than when they’d begun. She groaned as her body surged with power and size, limbs inching longer as muscles swelled and flexed. Eight feet passed by without a sweat, and Rarity’s bulk swelled alongside her. Her top, a mere line of bright red silk, quivered and then snapped. The sudden release of pressure was a breath of fresh air to the big, growing mare; Rarity exhaled deeply as her lap-filling breasts burst free of their prison, smacking weightily against her belly. Together, they had to weigh nearly a full hundred pounds, but to a mare who’d already passed a quarter of a ton, such a weight was nothing.

Her pants burst off soon after, now reduced to little more than a set of short shorts that less ripped than disintegrated, their tight, woven fabric exploding as Rarity’s thick thighs nearly doubled in girth. Her huge, fat cock lurched into the air, finally free from its bounds, the flare nearly a good five inches above the top of Twilight’s head. The rebound force from Rarity’s tearing pants sent her shaft smacking right up onto her chest, where it sandwiched neatly between her two massive, pillowy breasts. Rarity groaned with pleasure, squeezing her gargantuan tits between her hands on pure impulse. Vast tracts of titflesh oozed through her fingers as she increased the pressure, each jerk of her hips thrusting her cock higher and higher through her cleavage as it grew along with the rest of her body.

The heavy, almost masculine musk that betrayed Rarity’s arousal had suffused the laboratory nearly completely now. Twilight’s eyes were dilated, and she was staring up at her once-petite friend in awe. One of her hands had twitched downward toward her top of her crotch, and Rarity’s smile widened as she saw the blush on Twilight’s cheeks deepen. Behind her, Spike was rubbing his crotch with an almost brazen forwardness; Twilight may not have been able to see him, but from the bright red blush on his face, there was little doubt in Rarity’s mind that she had been intended to.

“Ooh,” Rarity groaned delightedly. “Now that’s much better.” She eyed the tattered remnants of the clothes around her with a sly smile. Her panties had torn off with her pants, leaving every inch of her large, bulky, and completely and utterly nude. Once, she might have shrieked at this exposure of a lady’s form—but now she knew that she was no mere lady. And a goddess did not shrink from a proud display to her subjects. So she smiled directly down at Twilight’s making sure to meet the little alicorn’s eyes as she continued to pump her thick, girthy shaft up between her immense cleavage.

Twilight’s pupils went up and down with it, the mare herself seemingly unable to keep from ogling the audacious display. A thick, virile stream of precum cascaded down the side of Rarity’s cock, lubricating its passage between her tits while promising a bounty of spunk from her groaning, swelling balls. Her testicles dangled low between her legs, reaching even below her needs as they filled anew with fresh seed. Each one bobbed lightly with the thrusting of her hips, smacking meatily against her fleshy thighs, their contents sloshing audibly. They may have been just a bit smaller than her breasts by this point, but they were almost certainly unspeakably heavier—their dense cargo made Rarity groan with tightness and arousal, and each schlick of her member between her vast, pillowy breasts made her balls push her thighs a little bit further apart as they swelled with seed.

She caught Twilight’s eye again, her smile twitching like a cat’s. “Don’t you agree, Twilight dear?” she asked. “A body this beautiful—why, it would be a crime to leave it hidden!”

Twilight swallowed. “Um, yes,” she said. She sounded a bit shaken. She bit her lip, her blush flaring as Rarity gave a particularly loud moan. “You look...lovely.”

“Oh, but don’t I?” Rarity purred. She released her breasts, letting them squish deeply over the black girth of her member. She grabbed each of her enormous testicles in one hand, her palms barely managing to stretch across even a fraction of their surface. “I doubt there’s a mare—or stallion—alive who could compare to me.” She giggled, giving her balls a playful squeeze. A jerk of her hips sent them slapping against her chunky thigh, sending her bountiful ass and legs jiggling even as her tremendous nuts sloshed and swelled.

She stretched, almost feeling an urge to yawn with satisfaction as she felt her body lengthen deliciously. The tops of her knuckles nearly scraped against the top of Twilight’s twelve-foot ceiling, she noticed, her smile widening further. “Not since the Herdsians, anyway—and what am I, if not the inheritor of that legacy?”

Spike was nodding fervently, his head bobbing up and down almost automatically. Twilight nearly followed, but hesitated, biting her lip.

Rarity noticed that quickly enough. She took a step forward, and the ground shook beneath her gargantuan weight. Twilight looked up at her—and up, and up, struggling to meet the eye of a mare who now stood a good two feet taller than her (and change). There was doubt in her eyes—hesitance. And Rarity simply couldn’t have that.

“Go on, Twilight,” Rarity cooed. Her massive cock slapped against her chest, and Twilight trembled, sweat dripping down her forehead. Rarity simply loomed, and her stature made it simply impossible to ignore or refuse her. Which was all well and proper, Rarity thought. After all, a mare of her size deserved to be obeyed. “Won’t you take my measurements, dear? I have a desire to see just how big I’m getting.”

A stuttering, blushing Twilight agreed. Rarity stood patiently, a small smirk on her face, as Twilight tried—and failed—to measure her using her original tape-measure. Only after retrieving a larger heavy-duty one were they able to take her full measurements. Height: eight feet, five inches. Total breast width: three feet. Testicle radius: one-point-three feet. Cock length…

“Three-and-a-half feet,” Twilight announced, blushing madly. The measuring tape snapped back, and she stepped away, still trembling with fear and arousal from lingering at Rarity’s side. Rarity herself frowned, humming quietly in disappointment.

“Only that much, hm?” she said. “Goodness, but I do think it could be a bit bigger, don’t you?” She squeezed her breasts around her length again and groaned softly, a hefty spurt of pre splattering the tops of her breasts with salty, milky-white globs. “I think we can keep going.”

“I—“ Twilight stopped herself, gulped. The sheer confidence in Rarity’s gaze made her pause, wince, blush. “S-sure, Rarity. Just a little bit.”

Rarity did so love the way Twilight’s eyes tracked the gentle ooze of her precum down her breasts. She drew in a long, shuddering breath, hefting her two magnificent tits before winking down at the little alicorn. “A little bit, yes. To start.”

Twilight’s blush doubled. As she turned back to fiddle with the device once more, Rarity noticed—with a burst of amusement that her new vantage point allowed—that Spike had stepped off behind a row of shelves and shoved his clawed hand completely down the crotch of his pants. She licked her lips, wondering just how shameless he and Twilight would become when she got even bigger.

Just a little bit. Poor Twilight. Deluding herself with the thought that “just one more” might quench Rarity’s thirst for more. Rarity nearly laughed. She’d tasted power—tasted a size and sexuality beyond that which she’d ever even dreamed. The Herdsians were long since gone; she was the only inheritor of their legacy. Why, she might not ever want to stop growing…

If her previous growth spurts had been tidal waves, Rarity’s next one was a tsunami. It hit her with a roar of crackling energy, and she seized it, devouring it, egging herself on as she grew. “Yes,” she moaned, feeling her body swell bigger, larger, sexier. “More. More!”

The ceiling grew ever-closer; the floor began to crack beneath her weight. She felt her horn poke up against the bottom of the room above. A thick, heady feeling swelled in her thoughts; overcome with arousal, Rarity thrust her hips forward, fucking her magnificent tits as her monster of a cock throbbed and drooled with pre. So large—so soft—yet so round and perky and firm, her bust must have been a marvel of the world by now. And yet that was nothing compared to what she was becoming.

An errant step forward caused her to stumble, her massive weight sending her off-balance. Now over ten feet tall, and fast approaching eleven, Rarity wasn’t fat, not by any means, but her swelling breasts and ass had pushed her past the three-quarter-ton mark with what felt like barely any effort at all. Her new size, though, led her center of gravity to bob and bounce and sway—and so she found herself plummeting to the floor, smacking down on her impressively sized rear and sending tremors through the entire house.

“Ooh,” Rarity moaned. She had both hands wrapped around her cock, and was nuzzling her flare as it grew long enough to brush against her muzzle. She lapped at her dripping, drooling slit, gallons of precum rushing forth to be gulped down as her balls churned larger and fatter between her legs. “Mm. Ooh, yes.”

“Rarity!” A light of sobriety sparked in Twilight’s eyes, and she took a step back. “I—I think it’s time to stop now. You’re getting too big.”

“N-nonsense, dear,” Rarity groaned, her voice rumbling. She squeezed her magnificent tits around her member and moaned as an orgasm struck her. Gallon after gallon of hot, virile seed erupted from her tip, covering the ceiling and her own cleavage with stallion spunk as she grunted and moaned. Ooh, but she was getting so big. She hadn’t dreamed that anything could feel this good. She continued to stroke herself, soft coos of pleasure escaping her lips as she kept growing, her head inching upward as her enormous booty spread across the floor. “If anything, I’m still far too small.”

“Y-you’re amazing, Rarity.” Spike’s voice was timid, but proud; awed was the right word, Rarity decided. She cracked an eye open, only half-focused on pleasuring herself; Spike’s eyes were glittering with awe and lust and submission, his tail sticking out far behind him as his hand pushed further down his pants. Twilight glanced toward him, her cheeks red, then whirled back to Rarity.

“This is the last one,” Twilight said. “I don’t even know if we’ll be even able to get you out of the basement at this rate!”

Rarity could have laughed—would have, if not for the loud chorus of moans accompanying her pleasure. Why, a method of escaping the basement had long since made itself known to her—except she was still far too small to execute it just yet.

She gasped in pleasure and surprise as another growth spurt hit her. The sheer sensation of it sent her orgasming again, her mighty cock flexing and throbbing as it erupted with jizz. Twilight let out a shriek as a torrent of cum came rushing down toward her, engulfing her in white, creamy spunk and blasting her away. Rarity just moaned, squeezing and playing with her breasts as her orgasm continued, seemingly without end, her enormous balls churning and swelling as more and more of her seed covered the floor.

Her musk, masculine and spicy and thick, filled the room like an oppressive fog. No matter which way you turned, every inch of the basement laboratory was drenched in evidence of her godlike virility. The walls had been painted white with her cum, dozens of books had been splattered with spunk, the sheer density of her musk matting their pages with a moist, sexual damp. Rarity simply continued to moan—continued to grow—each new inch, each new foot a more powerful aphrodisiac than the last.

“Argh!” Twilight rammed into Rarity’s side, unable to get her attention in any other way. “Rarity, you need to stop growing! The spell has fallen into a feedback loop! I don’t know how to stop it.”

“Ooh, very good,” Rarity cooed. She could feel Twilight small form squishing against her wide flanks, the little unicorn’s ministrations only serving to excite her further. Even sitting down, Rarity’s head was beginning to soar toward the ceiling once more; her entire flank was more than a third as tall as Twilight was, and pillowy and sensitive to boot. “More. More!”

“You’re flooding the basement!” Twilight switched her efforts, and began trying to push Rarity’s massive cock up and away from her precious books and lab materials. It was enormously heavy—easily as heavy as a full-grown stallion—and just touching it made Twilight’s mind and loins burn with thoughts of sex. A single drop of Rarity’s precum oozed down onto her skin, smearing across her shoulder, and Twilight groaned. Her balled-up fists sank deeper into Rarity’s four-foot testicles, the massive, churning spheres almost eager to consume her, too. Tremors of pleasure, of subordination, of need racked Twilight’s body as she struggled to contain the orgasm that mere contact with Rarity’s seed brought upon her. “You—you need to stop! Rarity!”

But Rarity paid her no heed. If anything, Twilight’s efforts were more pleasurable than they were disruptive. She cooed softly, groaning as she massaged her bust. Twilight’s tiny hands upon her immense nutsack was less a force and more of a massage in itself. She could feel them swelling up larger with seed by the second, more and more of her ongoing orgasm splattering the ceiling.

With a mighty thump, Rarity’s massive shaft overcame Twilight’s best efforts to hold it up. It smacked down out of Rarity’s cleavage, leaving her boobs jiggling and bouncing, and hit Twilight right on the shoulder. Twilight went down with a grunt, her small body even thinner than Rarity’s mighty shaft, which pressed her tightly to the ground as the gigantic mare continued to grow.

“Spike!” Twilight hollered, her voice only slightly muffled by the two hundred pounds of horsecock pressing her to the ground. “Turn it off!”

The artifact glowed a deep, brilliant purple. With each passing second, the beam of magical energy surrounding Rarity thickened, darkened in color. Rarity’s moans filled the room, even as the water-level of cum on the floor rose to a good inch in depth. Spike gulped, tore his eyes away from Rarity’s massive form, and stumbled toward the artifact, his claws and ankles sloshing through a heightening pool of jizz.

“Come now, Spike,” Rarity murmured, still kneading her breasts as they grew ever-larger. She grabbed a nipple and tweaked it, giving a squeal of delight as the pleasure bumped her up another inch. She eyed the tent in his pants lustfully—at her size, it was tiny, but for a tall dragon like him, it was borderline obscene. A long, thick bulge of drake meat snaked down his thigh, a magnificent damp spot spreading across the fabric as his stiffness became—she could guess—unbearable. Spike gulped, taking a step unconsciously toward her as he stroked the curve his balls made in his pants.

Rarity’s smile widened, though she didn’t let up on her own stroking. She could feel her balls growing fuller already, and felt another orgasm coming on. Delicate, manicured fingers slid up and down a fat, black horsecock so obscenely male as to make the whole arrangement look patently ridiculous. “Surely you’d love to see a lady reach her proper size,” she cooed. She hefted her breasts in his direction, two massive mounds of titflesh that sent his eyes spinning with lust. “Simply let this...run its course.”

“Don’t listen to her, Spike!” Twilight choked out, still crushed beneath Rarity’s massive meat and potatoes. Rarity groaned as the churning of her balls squished Twilight’s plump rear beneath them, the sensation filling her crotch with heat as another few gallons of precum splurted out of her tip. Her head pushed up another few inches; she was now approaching ten feet tall sitting down, and had to be nearly twice that standing up. Twilight continued to sputter beneath her, her one free arm stretched out toward Spike. “She’s caught up in a feedback loop! All she can think of is more!”

More. Yes, Rarity thought, a trill of excitement in her throat. She giggled as she surged up another foot, and moaned as her enormous breasts began to leak. She squeezed them between her biceps, and cooed when warm, aromatic milk began to drip down her fingers. She rather liked the idea of more.

But Spike’s eyes had narrowed, and he’d bitten down on his lip. “I’m sorry, Rarity,” he said. “But I’ve gotta stop you from destroying the house.”

A pity. But somehow, Rarity felt no fear at the prospect of Spike or Twilight’s interference. She was too large, too powerful to be stopped now. What could they do? What could they understand? A low, throaty growl of lust and pleasure reverberated in her throat as she grew past eighteen feet, her horn now brushing the ceiling. Oh, being big felt so good—and she knew, deep in her heart, that she was only going to get even bigger.

Spike poked and prodded the artifact frantically. Buttons lit up beneath his dancing claws, tiles shifting, strange runes flashing on the surface before melting away in seconds. The beam of magic continued to flicker, changing in color, brightening then darkening, but never shrinking, never stopping.

Far from slowing or even stopping her growth, Spike’s efforts only seemed to fuel her further. He worked the device as quickly as he could, but each flash of magic only seemed to make the big and growing mare swell even larger. Rarity’s moans hummed through the room, each of her orgasms more productive than the last. And her size—oh, she was just so big! Focusing on anything other than her huge, delicious body was proving to be an impossibility for any of them, let alone Spike, whose waistband had been straining against his erection ever since Rarity had first looked him in the eye. Now, though, she of course held quite a bit more height on him than before...and the thought made him almost wonder if he actually wanted her to stop.

“It’s not working!” he called out. “I don’t know how to turn it off!”

“Just—press the switch!” Twilight grunted, struggling not to be crushed beneath Rarity’s expanding stallionhood. “Just—mmff!”

“Twilight!” Spike watched Twilight disappear beneath Rarity’s gurgling, churning ballsack with horror, even as the gigantic mare herself moaned, masturbated, and continued to grow. All of Spike’s efforts were meaningless, it seemed—each dial or tile he pushed only served to make her even larger. Grimacing, he gave off a grunt of frustration and punched the artifact on the side.

The device went flying off of the side of the counter, struck the floor, and smashed into a thousand pieces. Spike gaped down at its remnants, eyes wide, as the crystal shards that had once made up its interior dissolved into sparkling purple magic. The energy flared once—and then darted toward Rarity’s herculean form with a speed that belied belief.

“Yes,” Rarity moaned, her body greedily sucking up every last drop of magical energy that it could. Her growth halted for a moment—before she simply ballooned outward, nearly doubling her size in a fraction of a second. She found herself doubled over, crouching on her hands and knees as her gargantuan body grew to fill the entirety of the space the basement provided.

Her shoulders rubbed against the ceiling, cracks spiderwebbing across its surface; her huge, fat rear jiggled and shook as vibrations from her exploding growth forced it more tightly against the wooden floor above. Rarity cooed and moaned, pumping her hips forward faster and faster as the basement grew tighter around her, fucking her own tits with a mindless intensity fueled by an ever-growing need for more. “Bigger,” she moaned. “Bigger and bigger and bigger—“

Spike found himself backed into a corner, staring with horrified arousal down the length of a gaping cockslit wide and deep enough to swallow him whole. With each foot Rarity gained in height, her massive body pressed against the walls a little bit more, the floor cracking beneath her immense weight. Her moans and musk dominated his senses; even as Spike pressed himself against the far wall, trembling as Rarity’s cock crept toward him, he found his hand thrust deep into his pants, pumping around his shaft as quickly as he could. Even the memory of Twilight, trapped beneath Rarity’s massive nutsack, only served to fuel his arousal even further; short, cute moans slipped through his lips as he imagined being crushed beneath those enormous testicles, feeling those oceans of sloshing seed pressing against his body as he humped and licked and worshipped them like the wonders that they were.

The ground began to shake. The very earth trembled as Rarity’s bulk grew to fill the basement. The ceiling cracked, splintering as the massive mare’s back rubbed against it. Spike gave a panicked “glurk!” of surprise when Rarity’s growing cock finally smushed him against the wall, pressing his tiny little body against the cement as it swelled and thickened. Spike gasped for air, both from pressure and from pleasure, as the wide, slick walls of Rarity’s cockslit swallowed his own twitching erection, his pants long since discarded among the rubble below. The ocean of cum was five feet deep by now, sloshing around Spike’s chest as he groaned and gurgled, pumping his boner into Rarity’s pulsing slit as the mare herself drew in for a final, earth-shattering growth spurt.

Outside, an ominous vibration filled the air—and then the Golden Oaks Library exploded with a sudden, incredible force. Nearby onlookers shied back from reflex, covering themselves as twigs and debris showered down upon the surrounding area. In the midst of the wreckage, a vast, towering form slowly drew itself up into a kneeling position, its shadow falling over the rest of the property.

...Scratch that. Its two shadows.

It was only when any onlookers unlucky enough to still be in the blast radius realized that the second tall form was not in fact, another figure, but rather a towering pillar of jet-black flesh that a low, rumbling moan filled the air. The gigantic Rarity, her thick thighs squished against the backs of her heels, gasped in pleasure as her growth spurt petered out, leaving her head towering a good fifty feet in the air—without standing. Her massive shaft, at least half that size, pushed up through her enormous cleavage, its girth shoving them rudely apart as uncountable volumes of salty, musky precum ran down the sides. Rarity’s head pushed back, her tongue lolling out of her mouth as her eyelids flickered—

The earth cracked beneath her as she thrust upward, driving her enormous tool between her breasts with a powerful, forceful motion. Each breast must have been nearly a third as tall as she was, and heavy and firm enough to jiggle and bounce with uncountable waves of motion from the force of the impact. Just as Rarity’s moans reached a fevered peak, the bulge that had climbed toward the top of her horsecock paused, swelled—and then erupted in a blast of pure, world-ending white.

Gobs of creamy spunk the size and weight of wagon carts crashed down upon the surrounding countryside. Ponies gasped and screamed, their efforts at flight thwarted by the oncoming rush of cum, a tidal wave of seed that washed over every road and house in a half-mile radius. And above it all, moaning and kneading her breasts around her thick, impossibly long shaft, was Rarity, each errant twitch and groan of pleasure driving her head further up into the sky.

Her orgasm went on for minutes, each throb and lurch of her cock sending her whole body seizing up as a pair of testicles large enough to swallow up entire herds of smaller ponies sloshed and groaned with weight and fullness. Rarity savored every foot, every inch of her size, as aftershocks of pleasure and sensuality rocked her huge body. Even the tallest house in the town only came up to her nipples now, and she was only getting bigger…

When she finally finished cumming, Rarity exhaled slowly, a long, rumbling sigh that sent her breasts and rear rippling with motion. She shifted her weight back, the earth trembling beneath her as her ten-foot Cutie Marks jiggled and bounced around her thighs.

When she at least opened her eyes, Rarity found herself staring around at the now-tiny town around her. “Oh, my,” she murmured, gazing down at the roofs of the houses beneath her. If she’d tried, she likely could have crushed any one of them with just a single one of her breasts—let alone her massive, weighty cock. The thought excited her—after all, she was a goddess now, and it was a goddess’ right to impress her subjects with her size and power—and she felt herself growing hard once again.

And then she felt it—just barely—but enough to notice: a small, gentle stirring atop her swollen medial ring. Rarity blinked, then glanced downward between her cleavage. Perched atop her shaft, his claws flexed and digging into the soft flesh of her gargantuan cock, was a small, scaly purple shape that trembled with exertion.

“Hello, Spike,” Rarity purred. She moved a finger beneath her ring and brushed it against Spike’s rear. He gave a grunt of surprise and let go, collapsing on her open palm a second later. She drew him up to her muzzle, smiling kindly down at him as her own shaft throbbed and stirred atop her massive nutsack. She was rather pleased, she had to admit, at the small puddle of white Spike’s own dripping cock had left in the lines of per enormous palm (though of course, it was far from anything compared to her own output).

“Um.” Spike visibly swallowed. His voice was small and tinny, especially compared to her own, rich, rumbling sound. “Hi, Rarity. You’re awfully…”

“Big?” Rarity laughed, the vibrations of it sending tremors through the ground around her. “Oh, I know darling. And I have you to thank for that.” Her smile became catlike, and she petted Spike’s back with a finger nearly as tall as he was. “Tell me, Spikey dear...”

His eyes widened. He nodded frantically, and Rarity’s smile widened. Excellent. A male willing to please his goddess.

In any way possible.

“Do you think,” she purred, “that perhaps I could get even bigger?”