It was a calm and peaceful day in the sunny little town of Ponyville. On the edge of this town, where the houses began to thin out into the bright, grassy plains of Central Equestria, a new, very small house had gone up over night. It was a very simple thing, no more than a single floor in height, constructed out of flimsy wooden planks and a few heavier supports.

Pinkie Pie had invited her friends over to this shack which she called her “Special Party House” for a very special kind of party. The door swung shut as the last of the invited arrived, curious to see what the pink pony had in store for them in such a tiny dwelling. There she stood, in the middle of the one-room box with a rather odd look on her face.

“Pinkie…?” asked Applejack. “You ok over there, sugarcube?”

“Y-yeah! I’m-mmm~ I’m great, App-oooh!” The earth-pony was standing in the centre of the room, her legs quaking with sweat dripping down her body. Behind her, another set of legs wiggled in place. They were grey, with either flank sporting a collection of bubbles.

With a stomach-turning SCHUULGHPP Derpy Hooves appeared behind her, holding what looked suspiciously like a giant, club-shaped stage prop, taken from the recent reenactment of Alice in Humanland. Both of them were covered from head to hoof in some sort of liquid.

“Ok, I’m all done!” Derpy chippered in delight. She placed the “club” on her back and stumbled about on her way past everyone else, a drowsy-looking smile on her face, as if she was completely off-her-hooves drunk.

Applejack wrinkled her nose at the wall-eyed mare. Whatever she was soaked in, it smelled like a very strange mixture of sunflower oil, sprinkles, and something… bodily.

“Thanks a lot, Ditzy!” Pinkie called. With her eyes occasionally glazing over, she moved her behind from side to side with a grin. She looked back to her confused and/or furiously blushing friends. “Well then, you’re all here!”

“Yes we are, Pinkie,” Twilight replied. “Mind telling us what this is about? I don’t see any streamers or balloons…”

Pinkie’s eyes darted about the room, before she put on a very large, very strange smile. “This party needs no streamers or balloons!” She spun round so that her backside was facing her friends, revealing what Derpy had been doing back there. Pinkie Pie’s rump was engorged beyond belief, the flanks spreading out as if their owner had suddenly put on fifty pounds or so. What everyone found their gaze drawn to, however, was the shadowy abyss staring back at them: Pinkie Pie’s butthole.

Three of the onlookers felt like throwing up, one of them did, while the last stared fixedly at it with her wings rapidly rising into Extreme Boner position.

“Is… that… what I think it is?” Rainbow Dash asked, almost unable to believe her eyes.

“Yup! I’m all lubed up and ready for all of my wonderful friends!”

Her wonderful friends, save for Rainbow Dash, were rapidly backing away towards the exit. Suddenly, Twilight turned and bolted for the door, only to slam into something solid blocking it from the other side. She looked across it, alarmed, and shoved at the flimsy wood. It didn’t budge.

“Move over, sugarcube!” said Applejack, sounding equally panicked. “I’ll deal with this.” She raised her back legs and dealt the door a heavy blow. The sound of cracking wood signalled her victory, only for the would-be escapees to get a nasty surprise.

“Wait, what’s going on??” Twilight cried as the broken boards were torn away. Behind them stood an impenetrable golden forcefield, clearly of Celestia’s design. “Princess? What are you doing!? Let us out! She’s gone crazy!”

“Hey! This ain’t the shit, Pinks! Let us out!” Rarity exclaimed, oddly.

Applejack looked back to Pinkie Pie with a furious, yet clearly scared look on her face. The wide-laned mare was in the process of tempting Rainbow Dash closer, seductively squishing at her fattened behind with both forehooves. “What’re you plannin’, Pinkie?” Applejack asked with a scowl.

Before Rainbow could get any closer, Pinkie pushed her away again, much to the pegasus’ annoyance. She clapped her hooves together to gain everyone's attention. “Ok, so you may be wondering why the Princess has betrayed you to my carnal desires…”

“Let us out already!” Twilight cried, images of what was to come flitting through her mind. “I’m not permitted to use my magic against the Princess’!”

Pinkie continued, unabated. “And that’s because we’ve come to a realization that something needs to be done about all of you.” As she said this, the smile turned malevolent and the air seemed to thicken almost as much as Pinkie’s own behind.

“You’re going to kill us?” Rainbow asked, raising an eyebrow.

Pinkie snorted with laughter. “Pff, no! Of course not! Look, you’re all here right now because something has gone wrong with each of you.” She pointed an accusing hoof at Twilight. “First of all, the Princess says you’ve become way too afraid of using your powers!”

Twilight took a step back, only to remember that there was nowhere to run. “But I can’t use my powers!” she cried in response. “I’m an Alicorn now, and that means the slightest miscalculation on my part could end up blowing something up! I can’t even get my levitation right without accidentally flinging ponies everywhere!”

Pinkie Pie completely ignored Twilight’s response and now pointed her hoof at Applejack. “You don’t trust any of us any more!”

Applejack shuffled her hooves and spared a glance in Twilight’s direction. “Well, that’s kinda connected to Twilight’s problem for the most part. And whatever the hay happened to Rarity…”

The fashionista-turned-whatever shot a glare at the farmer, her various pieces of jewelry and piercings generating little clinks as she moved. “You what, Jack? You got something against my new gems?”

Applejack stepped closer, narrowing the distance between their scrunched noses. “Not really. It’s just that I’m havin’ myself a hard time believin’ that you haven’t been replaced by some… extremely out-of-character Changeling.”

Rarity turned her nose up at the farmer, which was oddly the most Rarity-thing she had done all day. “Me n’ the Dogs have enough gravel to dig through to deal with your crap, AJ.”

Ok, good start, Pinkie thought to herself as she watched them argue. Let everyone get acclimated to their environment… She felt her widened entrance starting to give, and decided it would be best to begin. She clapped her hooves again. “Ok, now that I’ve given you all my reasons, I’ll let Rainbow Dash here demonstrate how I’m going to ‘reharmonize’ each of you!”

With that, Pinkie pointed her gaping anus at Rainbow’s face and simply waited. Rainbow blushed again, swallowing a lump in her throat as she considered her options. She could wait it out until Pinkie felt like explaining, in detail, what she wanted her to do. Or, she could go ahead and stick her hoof inside that giant, squishy cavern, and become the blissful shame of all of Ponyville. Assuming word got out.

“So, err…” Rainbow glanced between Pinkie’s seductive eyes and her dream come true a few times. “Why am I here? What’d I do wrong?”

Pinkie Pie shrugged. “I dunno, but Celestia wanted me to punish you as well.” She winked and moved her butt closer.

Rainbow’s eyes went wide as she realized she could feel the heat radiating out of Pinkie Pie’s insides. It was like a fleshy beach, getting boiled by the summer sun. I’d like the sleep in that tanning bed, Rainbow thought to herself with a perverted smile. She briefly looked to the others. Applejack and Twilight had their teeth gritted in anticipation, though it wasn’t because they were enjoying themselves. Rarity looked indifferent and simply picked at one of her earrings, apparently uninterested in the crazy situation.

With nothing else for it, Rainbow slowly reached up with a hoof and placed it against Pinkie’s soft, cushiony insides. The hoof dipped into her flesh for a good few centimetres before she even began to feel any resistance. Rainbow silently Woah'd to herself as the small rolls of Pinkie’s rectum came into contact with the tender underside of her hoof. The sensation was like soft, wet silk, if silk was the inside of a baker’s ass. In contrast to the cool morning air, Pinkie Pie seemed to have worked herself up into a hot, sweaty state, likely thanks to what Derpy had been doing to her just before. It was surprising she wasn’t letting out steam.

The thought reminded her of farts. She frowned in annoyance at the sexual roadblock, and cautiously leaned in to have a sniff. She quickly pulled away, looking confused. “Why does your butt smell like icing sugar?”

“Yours doesn’t?”

Rainbow blinked and decided not to dwell on the thought. Swallowing again, she slowly moved her hoof inward, across the base of the opening, before running it up against the walls as curiosity took hold. The inner walls of Pinkie Pie’s butt were surprisingly soft considering how stretched they already were. The edges of the entrance had been slowly closing as that tension returned to the muscles. They began to brush against Rainbow’s forehoof, and she gasped at the sensation.

“Come on, Rainbow, don’t be so shy!” Pinkie Pie encouraged her. She raised her back end a bit more, prompting Rainbow Dash to start pushing her hoof further in.

Rainbow Dash did as she was told and plunged her hoof in, deeper and deeper. It was only once she reached her elbow that the tunnel came to a stop, but it was enough. It was more than enough. Pinkie tensed up, bringing her walls collapsing down around her friend’s leg. The sensation of hot, meaty moistness wracked through Rainbow’s body and she let out a desperate moan.

“Oohhh! P-Pinkie! You feel… absolutely amazing!” she exclaimed. Her free hoof moved down between her legs and she shamelessly began to rub at her leaking lips. Pinkie’s hole was pressed tightly around her leg, forcing Rainbow Dash to have to pull against her muscles to remove it, only to plunge it back inside immediately after. “Oh, fuck!” The walls instinctually contracted at the motion, making the second dive even tighter than the first.

From the sidelines, everyone else watched as Rainbow Dash began ploughing Pinkie’s plot at a faster and faster pace. The butt plug had done its best at widening the entrance, but the constant motion of Rainbow’s hoof was helping to keep it that way. There was now a constant shlicking sound filling the shack, from both the lubricants coating Pinkie’s insides and Rainbow Dash herself as she forced her other hoof against her clit, delving into a state of mindless pleasure.

Twilight stared at the scene in absolute disgust as she wiped the last drops of puke from her mouth. She could still feel her stomach turning, yet she found herself unable to look away. Is this what Pinkie plans to do to all of us? she thought. How is this, in any way, “reharmonizing”? Surely we could have just talked it out instead of having her rape us all?

She felt a tapping on her shoulder and she looked to see Rarity giving her a disapproving look. “I know that face anywhere. You’re thinking Pinks ain’t got it in her, aren’t you?”

Twilight felt her eye twitching at the sound of Rarity’s new “streetwise” tone. “I really have my doubts that she’s serious about this,” she replied. “She may be crazy most of the time, but she’s never done anything like this before.”

“You think this is just some prank?” Twilight hesitantly shrugged. “If you think she’s gonna stop at this, then you don’t know Pinks for shit, Twi.”

“You don’t have to swear about it,” Twilight commented with a frown. “Just what exactly happened to you at Rambling Rock Ridge last month, anyway? One minute you’re a delicate, unendingly posh fashion designer, and the next you’re… this.”

Rarity stood up and folded her forelegs, the disapproving look returning. “It weren’t just one minute, Twi. You left me with the D-Dogs for the thick of a week before you got off your shitless flanks to ‘rescue’ me. By then I’d discovered the style of the gang.”

“But how in the hay did that happen?” Applejack cut in.

Again, Rarity turned her nose up which, as her friends had come to know, meant the conversation was irrevocably closed. She trotted away to another corner of the room, putting a wide, awkward gap between herself and everyone else.

A shivering yelp came from the middle of the room as Rainbow Dash reached her climax. She let out hot, steamy breaths with her normally tough back legs turning to jelly where she stood. She slowly lowered herself to the floor with a small sense of embarrassment starting to well up at the sight of her soaked hoof. Done with her fun, Rainbow pulled at her leg lodged in Pinkie’s anus, only to find it stuck.

“Wuh? Heh, Pinkie, let me out now… I’m all done,” she said.

Pinkie’s only answer was a knowing smile, her powerful butt muscles still clamping around Rainbow’s leg. With a strong, skillful flex, Rainbow was pulled up just past her elbow into the meaty space. “You’re not going anywhere, my little makeshift dildo~” She giggled and pulled again, this time with Rainbow Dash pulling at her leg to break free. Instead of making headway, Rainbow found her second forehoof vanishing into the ring of flesh.

She quickly pulled it back out, Pinkie’s butt hole not having much leverage over it yet. “Pinkie, what in the hell are you doing!? You can’t possibly take both my legs, you’ll rip apart!”

“That’s what you’re worried about?” Applejack asked as she cantered up behind her. She wrapped her own forelegs around Rainbow’s middle and pulled the pegasus away. “Come on, let her go, Pinkie Pie! Body parts belong on the outside!”

Pinkie raised her back legs, but to their surprise, she wasn’t gearing up to buck them away. Instead, she gently positioned them on either side of Applejack’s shoulders with Rainbow’s head trapped between them. “Look at yourself, Rainbow. You know you want this, you already felt how lovely and comfortable my butt can be on the inside. Just let me pull you in a bit more, it’ll feel awesome!”

“Eheh, I’d really rather not, Pinks-”

“What, you’re callin’ her that too now?”

“-I’m kinda starting to feel really silly and totally, completely and utterly embarrassed about this whole thing please let me go now. Please. I mean it, this has been fun and all, but I will literally start punching and kicking if you don’t let me go.”

Pinkie giggled again and put on that face she always wore, the one that knew way more than it let on. “Pff, as if that would stop me. I’ve been thickening my plot for this very day for about a month now!” With her muscles still wrapped tightly around her prey, Pinkie suddenly clamped her back legs around Rainbow’s head and forced it downwards. “Your resistance is futile!”

Despite combining the forces of the team’s fittest and strongest members, they were still no match for the seemingly unbreakable might of Pinkie’s backside. The pulling of the inner muscles suddenly turned into an inescapable black hole of death. Rainbow’s head was positioned so that her muzzle was in line with her lost forelimb, and so as Pinkie took a few steps backwards, the pegasus found her muzzle quickly being engulfed by the hungry backdoor. The strong scent of various kinds of sugary products filled her nostrils, causing her mouth to wet in anticipation for the nonexistent treats. Still, the sensation was as overloading as it was enticing, and Rainbow Dash found her limbs going slack.

Applejack redoubled her efforts to pull her friend free of her other friend. “Twilight! Do somethin’ already, cutsarnit!” she cried as she felt Rainbow’s struggling starting to cease. She looked down to see that pair of blue wings raising back into position, a faint pink blush appearing on their joints. Rainbow Dash seemed to be enjoying her predicament.

In one corner of the room, Twilight sat shaking with stress with her eyes glued on what was happening. “I can’t!” she shouted. “I can’t use my magic in this situation, it’s not allowed!”

“The hell do ya mean it’s not allowed!? We’re about ta lose Rainbow inside of Pinkie cus’ of you!”

Rainbow Dash plucked her muzzle out of the hole, quickly replacing it with her other forelimb. “Honestly, I’m kind of into this now,” she admitted with a wavering grin.

“Wh-what’re you talkin’ about? You were just tellin’ Pinkie that you’d beat her up if she didn’t let you go!”

Rainbow Dash’s face had turned red and her eyes were starting to flutter as she gazed at Applejack. “I know, but… with you holding onto me like this. I dunno, I think you’re setting off some instinctual urges, like my body thinks you’re a stallion about to start ploughing me. Heh, that’s funny, I’ve never really thought of domination being something I was into before.”

A few moments of stunned silence passed before Applejack looked down at her waist. Sure enough, her flanks were pressed up against Rainbow Dash’s at the perfect position for strap-on duty. Without a word, Applejack stared her in the eyes and let go, sacrificing Rainbow to the depths. Her head vanished as Pinkie stretched to accommodate it. After that it was over in mere moments. Everyone watched in horror as the hole slurped up the rest of the willing pegasus like a giant, blue noodle, with the only thing left outside being her back hooves. Pinkie let out a cry of ecstasy as her insides were suddenly brimming with one of her friends. Applejack tumbled backwards as Pinkie sat down, her prey pushing against the ground to get further inside. A Rainbow Dash-sized bulge swelled up in her stomach as she reached the end of the trip.

“Rainbow Dash, no!” Twilight cried

“Yum!”

“Applejack, what the hell!?” Twilight shouted in panic. She pointed her horn at Pinkie, ready to try and teleport Rainbow Dash out… and stopped herself. With gritted teeth and a quiet, frustrated whine, she reminded herself of what had happened last time she had tried using that spell - tired of losing book and quills, she had conducted a test on an orange by tagging it with a tracking spell, and found that all of her missing items were buried five miles underground. She couldn’t risk doing the same to a living pony.

For a moment, Applejack didn’t reply. She just stared at the shrinking hole in utter shock at what she had just done. She snapped back into the moment. “Well you didn’t help!” she angrily shouted back at the unicorn. “You just sat idly by while I was trying my hardest to save her! And now look!” She pointed at Pinkie’s wriggling belly. “She’s probably boiling in stomach acid right now!”

“I-I’m sorry! I’m sorry! I just can’t risk it!”

“Well maybe you should have, cus then Rainbow might still be- urk!” Applejack was grabbed around the neck by her cannibalistic “friend” and pressed close to her giant, soft belly.

“She’s fine in there, actually,” said Pinkie, smooshing Applejack against her tender body with a peaceful smile on her face; she was in love with the feeling. “Just listen to her moans of pleasure. She’s enjoying it so much, being trapped in my big, soft belly!”

Applejack pulled away. It was a far easier task than getting anything out of Pinkie’s titanium sphincter. She retreated to the wall of the shack, noting in her mind that there was nowhere to run. “Get the hell away from me! You monster!” she cried. “That’s it! You’re just a monster, you’re not Pinkie Pie! How in the hay can your… your stomach stretch enough for a whole pony in the first place??”

Pinkie shrugged. “I’m stretchy,” was the simple answer. She slowly turned back around, her mumbling bulge brushing the floor as she did so. “So, who’s next?” she asked.

-----

The world outside thought it was just any other day. Celestia knew better. She sat before the shack, her ears twitching in delight as she listened to the terrifying things going on inside. With Twilight legally and therefore morally unable to use her magic, her forcefield would stand strong until the deed was done.

“The things I come up with sometimes,” she mused to herself with a smile. While her forcefield was nigh-impenetrable, including the senses of sound and smell, she could still hear the arguing and shouting going on within, and the distinct waft of cupcakes and sprinkles rising out of the shack’s flimsy roof. “It brings a strange smile to my face, to be able to re-harmonize you all in such a crazy way and still get away with it.”

Beside her, Fluttershy held her ear against the golden field, curious, but unable to pick up on the sounds that the princess had no trouble hearing. The magic was warm to the touch, just like Celestia herself. “U-umm… would you mind please telling me what’s going on in there, Princess Celestia?” she asked.

The princess paused, thinking for a moment. “I suppose it would be only right,” she admitted in response. “As we speak, Pinkie Pie is putting your friends through an important trial, something that will stretch their friendship to the absolute limit. If they pass, then their friendship will be far stronger than before, but if not, the Elements of Harmony may be losing a member. Two if we’re unlucky.”

Fluttershy gasped in horror at the prospect. “But… wh-what do you mean? What could be so dangerous that it would tear our friendship apart?”

Celestia pointed at the shack as her horn lit up. The smile was gone, replaced by the oddly neutral expression Fluttershy had seen her use from time to time. The pegasus look back to see a hole forming in the shield and the wooden wall behind it, revealing the strange scene within.

Fluttershy frowned. “I don’t understand what’s going on. Why is Pinkie Pie so big all of a sudden?”

The princess leaned in close, her smile reemerging. “Imagine this,” she whispered, her voice taking on a sultry tone, “you’re out in the woods, all on your own. There isn’t a critter to be seen and you’ve gotten yourself completely lost amongst the trees…” With a flash of magic the view port into the shack vanished, and everything around them was replaced by a dense forest.

“P-Princess?” Fluttershy called into the chilly evening air. Sure enough, she was alone, and there wasn’t a single scuttle or chirp to be heard. “Wh-... where are we? Princess??”

“Exactly where it looks like; in the middle of nowhere,” came a voice from behind her. Fluttershy whipped around and quickly sank to her knees as the shape of a giant snake rose up before her. The white-scaled creature slithered out of the shadows, its golden patterns glistening in the orange light of the sunset. “Imagine the mess of emotions you go through, when you come to realize that you were being followed, hunted, this entire time,” spoke the Celestia-snake, flicking its tongue as its emotionless eyes zeroed in on the helpless pegasus.

Fluttershy turned and ran, her wings instinctively locking against her sides out of fear. She soon lost the sensation of the leaf-covered ground beneath her hooves as she was raised into the air. The snake’s tongue was glowing with the same golden magic as Celestia’s horn. She let out a shriek as its maw stretched wide enough to swallow her and all of her friends whole.

“Imagine the terror,” Celestia continued, “as you see your inevitable doom closing in on you. A show of the ultimate kind of authority, and proof that you are nothing more than a meal to this predator.” Fluttershy’s flailing hooves landed against the snake’s gums. Before she knew what was happening, the magical vice was released and she flopped onto her flanks on the squishy, saliva-covered seat. “The conflict that appears in your thoughts, as you realize how much you’re enjoying it.”

Fluttershy was shaking in fear, but Celestia’s words caused her to pause. She had had dreams like this. Exactly like this, in fact, where she was trapped in the sticky maw of a hydra with no hope of escape. She slowly looked down at the juicy gums of the snake pressing against her legs, and suddenly realized they were shaking.

“O-oh…?” As the snake’s tongue coiled around her midsection, Fluttershy felt a special kind of heat emerging from her nether regions. It was then that she realized she could feel Celestia’s hot breath wafting out of the gaping throat awaiting its meal just behind her. Pushing aside thoughts on anatomical accuracy, Fluttershy looked back with a hot blush coming over her face.

“Some of us need a little bit of crazy in our lives,” said the snake. “Pinkie Pie is no different. She’s going to swallow up her friends one by one until they’re all sleeping cozy and tight in her stomach. The others might not see it yet, but she’s doing them a favour.” The black tongue grew longer and tied itself around Fluttershy’s whole body.

“I-it’s… cold out here,” Fluttershy spoke numbly, before allowing herself to fall gently into the abyss.

Fluttershy opened her eyes and frowned; she could feel grass under hoof once again. Looking around, she saw that she had been transported back to the shack, with Celestia standing over her. “Wh-what? What just happened?”

“Hey,” Celestia began. She wore a deep blush on her face as she stroked Fluttershy’s mane. “How about, tomorrow, I take you to Canterlot where we can have some real fun with each other?”

Fluttershy’s eyes went wide as she realized what she was being offered. “M-m-ma… I-I…”

“I’ll take that as a yes,” Celestia cooed, before giving the little pegasus a kiss on the cheek.