The town of Ponyville.

A sleepy, quiet farming town nestled in the rolling foothills of Mount Canter.

And, like most days, today this sleepy town is under attack!

Through the streets and boroughs, as far as the eye can see, Ponyville is under siege by hoofball sized gelatinous invaders!

They rolled, bounced, and jumped along, not attacking per se, but still crashing into everything with the heft of an overweight foal and the speed of a fit one.

And, as usual, most of the Ponyville population had either hightailed it for the hills or bunkered down in their root cellars. But they could rest easy knowing that their crack team of commandos, their homegrown first-responders, their catastrophe-correcting A-Team would soon set things right.

But there was only so much you could expect six ponies and a dragon to do against a veritable army of squishy invaders.

"Ah, here we are. Slimes." Twilight read from a hefty book of obscure Equestrian fauna, not even looking up to fire a concussive blast from her horn every time Spike cranked her tail. "Small but highly adaptable. Slimes are an amorphous monster native to marshes and other boggy areas. Though low in both intelligence and threat level on their own, in large groups their tendency to consume anything in their path can lead to destroyed crops and property. Often blue and ranging in size from an apple to-"

"That's all very interesting darling," Rarity interrupted from Roseluck's flower stand where she was keeping five slimes at bay with a broom, "But does it say anything about how to deal with them?"

Twilight's concentration wavered, and a sightly too-powerful blast flipped a wagon, spilling its contents across the street. She winced at the destruction, but a group of slimes had already converged to eat the evidence. "Sorry! I'll skip ahead."

She flipped a page of her reference guide as Spike rotated her like a turret towards the next cluster of slimes.

"In certain circumstances, slimes may evolve into higher variants based on their diets. These variants outclass their pre-evolved forms by every metric, but especially in the breadth and strength of their abilities. A slime that has evolved multiple times can be considered a significant danger even on its own. The most common variants include sticky slimes, grass slimes, spark slimes, water slimes, fire slimes-"

"Whoa nelly! Found a fire one!" Applejack called out as her second-favorite lasso was reduced to cinders. "Any chance of you skipping ahead to something helpful, Twilight?"

"I'm looking!" With a jerk of her head, another blast went awry and gave some poor pony a new Prench window. "Oops."

"Less apologizing, more firing and reading." Spike reminded her. "Just leave the aiming to me."

"Got it," she replied and tucked her head back down. "But I'm almost at the end of the chapter!"

"Try reading just the last couple lines." Pinkie suggested. The party mare was occupying her time trying to juggle as many slimes as she could at once. Surprisingly, they seemed okay with this situation.

Not hearing a better plan, Twilight scanned down to the last line of the page and read: "The last of the slimes were defeated and sealed in an impregnable vault by Her Royal Highness Princess Celestia around year 550 of her reign."

For a moment, silence reigned in the square. Silence, aside from the noise of many, many slimes squishing and bouncing and rolling over everything.

"I don't mean to be rude," Fluttershy spoke up, reminding everyone that she was also present. "But I'm starting to think that maybe Princess Celestia isn't actually all that good at long term solutions for monsters and other bad guys."

"Ah ha!" Twilight apparently tuned out the criticism of her teacher. "If Celestia dealt with them before, then surely she'll know their weakness." With a flash of magic, she teleported into existence a quill and paper and began to write. Seeing her distracted, Spike took over the offense, blowing thin but intense streams of fire at any slime that came too close. It didn't seem to particularly hurt them, but they shied away all the same.

"Ready!" Twilight tossed the scroll in the air. Spinning on a heel, Spike switched gears from 'regular fire' to 'mail fire' and sent the missive away in an ashen cloud.

Applejack thundered around in a massive circle that tightened with every loop. But despite her considerable herding skills, the slimes refused to be corralled. Either they were too simple to be afraid or too distractible to stay in one place. "How long till she replies?"

"I don't know," Twilight admitted. "I marked the scroll as Urgent and she tends to respond quickly when I-"

Before she could finish, Spike cut her off with a fiery belch that materialized into a reply. He nicked it out of the air with deft claws and broke the seal.

"Give it here, Spike"

"No!" Rainbow Dash interjected, "You'll read the whole thing out loud like you do with every letter from the princess and it'll take way too long. Just give us the highlights, Spike."

Apparently agreeing with the pegasus, Spike held onto the letter and began to paraphrase.

"Dear Twilight. I offer my deepest apologies... blah blah blah... another of my old foes I thought defeated... blah blah... now falls to you and your friends." He flipped a page. "Truly, if I had known then I would have... yadda yadda yadda."

"Did she have this prepared?" Applejack wondered aloud, "There's no way she coulda written all that so fast." She spun and launched a hefty buck into a slime, sending it bowling back into a group of others who were sent flying from the impact. "Stee-rike!"

"Skip to how we stop them, please." A note of panic entered Rarity's voice. A slime had latched onto her broom head and seemed to be trying to eat it.

"Without hurting them! If, if we can help it, that is."

"I don't see what the big problem is," Pinkie commented. "These guys are loads of fun!" She cheerfully pronked across the square as some slimes teasingly ran away ahead of her while others hopped along behind like a row of ducklings.

"Found it!" Spike declared. He began to read from the relevant section. "You will find the slimes a challenging foe. They are difficult to grasp with normal telekinesis..."

"Found that out already!" Rarity confirmed.

"...and generally immune to lightning damage."

"Dangit!" Rainbow Dash swore as she abandoned the thundercloud she'd been building.

"So I have provided..." he trailed off as his eyes danced down the page.

"Spike?"

Suddenly, he ripped off the final page and held it up in front of Twilight's vision. "Here we go! Spell diagram modified to affect a slime's unique essence!"

Twilight stared at the diagram, burning it into her memory, before pushing the paper aside and lighting her horn. At first, nothing seemed to happen. She strained, sweat beading on her brow, and the corona around her horn grew even brighter. Slowly, one after another, each slime was surrounded by a soft pink glow of magic that twinkled and shone like a coating of diamonds.

"Ooh! Sparkly!" Pinkie commented.

Rarity wiggled her broom, hoping to dislodge its passenger. Much to her surprise, not only did the slime release, but it floated up into the air. It was soon followed by another, then another, then a dozen more. In under a minute Ponyville Plaza was filled with slimes all hovering at roughly second-story level in the air. They bobbed and dipped in the breeze, drifting like thick soap bubbles. Some tried to roll in the air, but with nothing to push against, they stayed put.

Twilight cut off her spell with a short breath of fatigue and gazed proudly at her work. "There. They should keep floating for a few hours until we can decide what to do with them. "

The immediate threat passed, Twilight's friends all gathered at her location.

"They don't look nearly so dangerous when they're just floating like that." Applejack commented.

"Uh, girls?"

"They're actually rather nice to look at," Rarity admitted, "Once their, ah, sliminess is no longer an issue.

Rainbow Dash gave one a light kick, sending it bouncing into the others like a billiards ball. "Flys pretty good. I bet we could make a new sport out of them."

"Hello? Earth to Twilight. AJ? Rarity?"

"Oh, please no." Fluttershy, no longer trapped beneath a pile of mini-slimes, spoke up in their defense. "They are still living creatures after all. I'm sure they didn't mean to cause all this trouble and that we could find a new home for them, somewhere where they won't be a bother to anypony."

"HEY!"

The whole group jumped in surprise. They glanced around, but none could place the voice.

"Up here!"

Their heads went up, and their jaws went down. Above them, Pinkie Pie floated amongst the slimes like a pony-shaped parade float. Despite her best efforts to doggy-paddle through the air, she remained immovably aloft. "Little help?"

"How in Celestia's name did you get up there?" Twilight demanded.

The airborne pony shrugged. "You did a magic."

"But that should have only affected the slimes..." She trailed off, grabbed the page of Celestia's instructions once more, and began reading it intently to figure out what she'd cast wrong.

Rainbow Dash buzzed the slime cloud and grabbed her friend, easily ferrying her back to the ground. Upon closer inspection, it was clear that the gem-like aura surrounded her too.

"See? I told you I was sparkly."

"This doesn't make any sense!" Twilight threw the paper to the ground. "I cast everything correctly. Princess Celestia's spell can't be wrong. So why did it affect Pinkie?!"

"Hey, there's no need to go loco over it," Pinkie offered, "Maybe I'm just special."

Twilight's head snapped up. "That's it! Maybe it's not the spell, maybe it's you. You could be covered with slime essence or something. Do you mind if I run a quick diagnostic spell?"

"Sure. Fire away!" Pinkie spread her hooves wide as though the spell was coming in hug form.

Rather than a bespelled hug, Twilight merely lit her horn. The crystalline glow faded from Pinkie as a new normal-looking glow took its place. Meanwhile, while Twilight debugged her spell, the others contemplated the still present cloud of slimes.

"So... Ah guess we can round them all up now."

"Yes, that we may. But there remains the issue of where to put them."

"There's, um, a field behind my cottage. I'm sure the other animals wouldn't mind sharing."

"Yeah, but what's gonna stop them all from just coming right back into town?"

"We could... build a fence."

"More like a wall, Ah'd say. Them slimes are hefty little critters."

"Hey, girls?" Pinkie cut in, "I think somebody should check on Twilight. I think I broke her."

Twilight was not moving. The spell was still active, judging by her horn, but the mare was not. She stood stock still, eyes wide, pupils small, and mouth agape. Pinkie waved a hoof in front of her face. No reaction. Pinkie booped her muzzle. Nothing.

"Here, let me get her." Rainbow Dash leaned in close and whispered softly in Twilight's ear, "Sup, Twilight. I don't have a bookmark, so it's cool if I just leave the book open, face-down, on the page I'm at, right?"

With a gasp like she was wakening from death itself, Twilight rebooted. "What? Book! No!" She shook herself back to her senses. "I... what... what was I doing?" Then her gaze met Pinkie.

"What? Do I have some slime on my face?"

Twilight took a deep breath in, let it out, then repeated it twice more until she was perfectly rational again. "Pinkie," she started slowly in a concerned voice. "I just performed a general diagnostic scan on you. And while I'm no doctor, I have every confidence that I cast it correctly. The second time as well." Her voice caught in her throat for a second, but she swallowed it back. "Pinkie, according to this... you're only half pony."

The whole group gasped, Pinkie loudest of all. "Oh no! What's the other half? It is cupcake? I know Granny Pie always used to say you are what you eat, but-"

"No." Twilight cut her off. "Pinkie... it's slime. According to this, you're half slime."

Pinkie's friends took a moment to digest that piece of news as they regarded her. After all, how is anyone supposed to react to a bombshell like that? To find out that your friend not only has a questionable heritage but a mixed-species one as well.

"Yeah, I buy that," said Rainbow Dash.

Everyone turned to her, their shock redirected.

"I mean, look how squishy these slimes are." Dash grabbed one from the sky and gave it a vigorous stretch and squash. It pulled like taffy and snapped back without trouble. "And Pinkie has got to be the squishiest pony I know." She grabbed Pinkie and put the mare through the same treatment. She stretched alright, not nearly as much as the slime had but still a lot more than a fleshy pony body should have been able to.

"To be honest, I always thought she was just kinda fat," Rainbow Dash continued with all the tact and delicacy of a sledgehammer, "You know, cause she's eating sweets all the time, but her being part slime makes sense too."

"Actually I'm pretty thin," Pinkie replied, glossing over or not even noticing the insult. She pressed a hoof against her torso and it sunk in alarmingly deeply. "My coat just has a lot of volume. I never really seem to put on any weight, not even after I tried to break the Canterlot cake-eating record."

"Of course!" Twilight said, brightening suddenly. She grabbed her book from where it had been placed and rifled back to the slime chapter. "It all makes sense now! Slimes don't store food as fat, they process everything they eat into energy almost immediately. And if Pinkie is part-slime, that's why she can live on baked goods alone."

"So that's how she does it," Rarity cursed under her breath, "She's been cheating!"

"This explains so much!" Twilight gushed as she scanned deeper into the sections she'd skimmed past. "So many things that we'd just dismissed as 'Pinkie being Pinkie' that can finally be explained!"

"Wait, wait, wait. Put some breaks on this party train." Pinkie stood up, her expression somewhere between concern and disbelief. "Twilight, how can I be only half-pony and- and-?"

"And half slime?" she supplied, "No idea! But that scenario does seem to satisfy the current conditions. And it would explain the strange... elasticity that you have."

Pinkie blinked. "My what now?"

"You know," Twilight said "That thing you do whenever you get overly excited or emotional? How your body stretches in strange and impossible ways? We always just called it 'Pinkie being Pinkie', but this is a much more satisfactory answer."

Pinkie mused on that for a moment, chewing her lip in thought. "You mean like this?" In a swift motion, Pinkie grabbed the tips of her ears and pulled them up, up, up until they stood like rabbit ears on her head.

"Yeah, I think you're the only one who can do that," Spike commented. Fluttershy looked as though she were about to squee in bliss from rabbit-Pinkie.

"Or this?" Letting the ears snap back into place, Pinkie spun her head around once, twice, three full revolutions. Even at 1080 degrees, her neck didn't look to be under the slightest bit of strain. Rarity turned slightly green at the sight.

"Y-yeah," Applejack said, not looking too great herself. "Like that."

"How about this?" With a quick spin, her head returned to normal. Pinkie stretched a hind hoof across her back and-

"Pinkie!" Twilight shouted. Pinkie stopped; One hoof so deep down her throat she could have grabbed her own stomach. Twilight sighed. "I think that's more than enough."

"So, you can't do those things?"

"Hay no!" Rainbow Dash practically shouted. "Do you even have bones?!"

"Of course I have bones. Wanna see?" Pinkie opened her mouth a little too wide for comfort only for Rarity's magic to clamp it shut suddenly.

"We believe you Pinkie, dear. There's no need to.. to... unsheathe your skeleton." She shuddered at the mere thought.

"Huh. I just thought nopony else did it because they just never felt like it." She shrugged. "Go fig."

"Wait, wait, back up." Spike stepped into the center of the group and grabbed their attention. "Even if Pinkie is half-slime, which, someone's got to say it, still isn't the weirdest thing we've found out about her, how could that have happened? They only just broke their containment in the Everfree today. "

Fluttershy nodded. "Serious doubts about the Princess' monster sealing abilities."

"Hey, yeah!" Pinkie chimed in. "Both of my parents are one hundred percent ponies, and I would know! I've known them all my life!"

"Well," Twilight concluded, "That's something you'll have to ask them yourself."

Pinkie paused at that, her expression turned... complicated. Deep thoughts were swirling. Thoughts that Pinkie didn't like one bit.

"Hey," she said, her voice much more subdued than usual. "Can you all take care of these slimes? I... think I need to go get some answers."

Everypony nodded. Her feelings were understandable, if difficult to relate to, and they all knew she'd have done the same for them if their positions were reversed. Twilight stepped over and laid a wing across her back.

"I'll go with you. For support." And also hopefully answers to her growing list of magical and biological questions, but now was not the time to mention that. "I can take us faster as well."

With a soft ripple of magic, the pair quickly teleported away.

Cloudy Quartz sat alone in her cottage, sipping from a stone cup of strong herbal tea. Though she wished to help her family in the fields, age was slowly claiming her body and today it had refused to give her the use of her lower back.

Thus, she was the only pony home to answer the door when the knock came.

Twilight and Pinkie Pie entered at her beckoning, but any hope that this might be a social call was quickly dashed. The unusually serious expression on her least serious daughter told her all she needed to know. And if that wasn't enough...

"Mother, we need to have a talk."

Cloudy Quartz set down her tea and sighed. "I had known this day must come. Though, in truth, I had thought it to come much sooner. Sit."

They did.

She lifted the kettle and poured the both of them tea. They were going to need it. "As I fear you may have guessed, Pinkamena's father is not her true sire."

Pinkie gasped but Twilight merely nodded.

"If thou hast uncovered that much, then you deserve to know the whole story. It was many years ago when I was a much younger mare..."

~~~

Cloudy Quartz worked alone in a field of rocks. Her body was young, having only birthed two foals, and spry yet enough for the task. Her husband worked another field while her mother-in-law watched the foals in the farmstead. Her task was tedious but not difficult, so long as she remained patient and focused.

Behind her, in a small copse of trees on the edge of the field, a shape moved in the brush. It twisted and warped, growing four legs and a long, sturdy neck. It walked out of the woods, slowly and deliberately on unfamiliar legs, right up behind the unaware rock farmer.

With a reach that seemed longer than it should have been, it stretched out a forelimb and clamped a hoof down on her shoulder.

"Ah!" Cloudy squealed as she jumped up and whipped around. But she just as quickly lowered her hackles when she recognized the face before her.

"Igneous!" she squeaked, "You startled me! Is there something the matter with the west field? Art the foals well?"

He said not a word but stepped closer, curling his neck around hers and making his intentions clear with a low purr in his throat.

Cloudy Quartz's normally pale face blushed a deep crimson. "Ig-Igneous! What hast come over you? Tis neither harvest festival night nor the anniversary of our Pairing!"

Still, he remained silent, letting his body do the talking in a language with which Cloudy Quartz was unfamiliar, but which she somehow understood all the same.

"I-I suppose... if you are so willing... t-then I would not be opposed to such a thing, even so... brazenly proposed." She yipped as he nibbled her ear slightly, her blush deepening even further." A-Alright then! But in the woods. Quickly! We shouldn't want the foals to see us."

~~~

"And then I removed my shawl and he removed his hat and we-"

"Stop, stop stop!" Pinkie demanded, her pink cheeks redder than a ruby-filled cherry pie. "I do not need the story of how Pinkie Pie was made!"

Cloudy coughed and regained her composure, the subtle blush fading. "Indeed. Mayhaps that is too much truth. After our... union, I returned to working my field and he to his. Or so I thought. When I spoke to Igneous that eve, he knew not of what I spoke. He claimed to have not left his field all day. A week later, I learnt I was with foal."

She turned her expression towards her daughter. "And naught four months later, you, Pinkamena, were born as hale and hearty a babe as any."

"So... dad... is not really..."

"Your father is your Father," the older mare insisted with an edge to her voice. "And he shall always be so. But though he is your father, your sire is somepony else. Possibly something else."

"A mimic slime." Twilight supplied helpfully from her book.

Now it was Cloudy's turn to look blank and confused. "Pardon?"

"A mimic slime," Twilight repeated, tapping the page in front of her. "It's right here in the book. A high-ranking slime variant with the ability to shapeshift into other creatures it's seen before. Your mysterious doppelganger couldn't have been a changeling as they can't create nonchangeling offspring, even when in disguise, and this fits her other abilities as well."

In all the mental rehearsals of this conversation that Cloudy Quartz had contemplated over the years, none of them considered the chance that Pinkie (or her friends) might know something about the matter which she did not. Such a revelation caught her off balance. "I... know not of such a creature, but if you say it to be true, then I have no claim to disbelieve you."

"So... does this mean I need to plan for two Sire's Day presents from now on?" Pinkie mused.

Before either pony could answer, they were interrupted by a puff of smoke that snaked its way into the room down the cottage's chimney. It stopped in front of Twilight and reformed into a torn napkin with a few scribbled lines. She snatched it from the air and read it eagerly.

"Oh no!" Twilight gasped, "Pinkie, we have to get back. The spell wore off early and the slimes are loose again!"

"Okay!" Pinkie hopped up, drained her tea, and gave her mother a quick hug. "Thanks for the tea and the truth, Ma! Love you, gotta go!"

Cloudy Quartz barely had time to process this and utter a quick 'bye' in return before the two ponies disappeared from her home. She sat back, refilled her tea, and took a long, slow sip as she considered the conversation. All in all, it could have gone worse. Now she only needed to find a way to explain it to Igneous.

They arrived to chaos, and not Discord's whimsical variety. Slimes once more roamed the streets and their friends had resorted to their original tactics to try and round them up. In short; they were failing.

"Twilight!" Rarity cried when she spotted their arrival, "I tried to cast the spell from the letter, but it didn't work."

Twilight nodded knowingly, "I was afraid of that. They've adapted already. I don't think it's going to work again so we'll have to think of something else. Pinkie, do you... Pinkie?"

"Hm?" Pinkie looked up from where she had been stacking several slimes in order of decreasing size.

Twilight paused, as the suddenly compliant members of the slime tower formed the wisps of an idea. "How are you getting them to stay still?"

"I gave them some jellybeans and they calmed down." Pinkie fished a few more out of her mane and passed them to the slimes. They slipped past the slimes' membranes and began to dissolve as the slimes undulated happily. Another one rolled up and nudged Pinkie, almost pleadingly. She fed it one and added it to the stack. "I think they like them."

With that, the final pieces of a plan clicked into place in Twilight's mind. "This is just a theory, but it's our best shot. If it really was a mimic slime that met your mother that day," they ignored Rarity's scandalized gasp, "then that essence would make you the highest ranking slime here. It's possible that they might acknowledge you as some sort of pack leader or alpha slime. There are quite a few cases where some monsters will accept food as a sign of fealty to a superior."

"Soooo..." Pinkie slowly digested that, "what you're saying is... if I feed all these slimes, then I can make them all my friends?"

Twilight hesitated. It was an oversimplification but... "Effectively, yes," she replied.

Like lightning, Pinkie was back on her hooves. One went into her mane and came back with a handful of confections. "I've heard that the way to making a new friend is sometimes through their stomach, but I've never tried it like this before. Come on slimies! Who's hungry!?"

In practically no time at all, every slime was fed and tamed. They waited patiently in a line as Pinkie walked by, giving each and every one a name. "And I'll call you Buu and Suu. And you can be Inky and Blinky. And I'm gonna call you Mister McSquishy!" When she was done, she hopped atop Blobobob, a rather large individual covered in tiny slime fronds like a limp sea urchin, and made herself comfortable like it was a giant beanbag. A few small slimes, two yellow and one blue, peeked out from within her mane. Her friends watched the show with a mixture of fascination and amusement.

"I'm glad everything got sorted out peacefully," said Fluttershy. "I do love it when we get to make friends with new creatures."

Applejack took off her hat to shake free a bit of stray slime goo and chuckled. "Ah'll say. Better'n locking them up to be somepony else's problem down the line for sure. And who woulda thunk it? Pinkie Pie: Queen of the Slimes."

"Oh, we are not calling her that," Rarity scoffed. "I'm sure we can do better."

"I dunno," contributed Rainbow Dash as she flew circles around a slime that had evolved a pair of slimy glider wings while fighting her earlier. "I think it sounds pretty awesome!"

"Ditto!" Pinkie agreed with a cheery wink and giggle.

An old idea. Had to rush the ending a bit to meet the contest deadline, but I'm glad I finally got this written.