Adventure Time With Fionna And Cake: The Legend Of Twilight Sparkle

by Slippin_Sweetie

Rating: teen
Tags: Comedy, Other, Adventure, Slice of Life, Crossover, Adventure Time, Alternate Universe, Human, Twilight Sparkle, My Little Pony: Friendship is Magic
Length: 2281

Writing alone in a private chamber the Ice King sulks. Writing his fantasies away as he envisions a perfect world where his characters Fionna and Cake go on epic adventures. This time he decides to add his latest obsession into his fan fiction.

Plagued by insanity, the Ice King writes away his ever growing loneliness by creating the perfect crossover fanfiction. His original characters meeting canonical characters from another franchise? When has that ever been done before? So many new and original ideas at work thanks to the Ice King's creative genius.

Adventure Time timeline placement: Somehwere in Season Five before the episode Betty. (S5 EP48)

My Little Pony Friendship is Magic timeline: Season 2 Twilight before Canterlot Wedding

Published 2022-11-29 22:50:00 UTC
Last updated 2022-11-29 22:50:00 UTC

What Time Is It?

Ice King slumped over his crowded work desk, stacked high with books and notes he had long forgotten about during his time as Simon Petrikov. The hundreds of personal letters and notes that were once made in desperate haste to slow the monstrous change that had already overwhelmed the young scientist long ago.

“Oh!” gleamed Ice King, picking up a stray scrap of paper as he examined the scribbles.

“Marceline’s wish list….hey, maybe I can use this to get a piece of that vampire action!” chuckled Ice King.

Upon further inspection, the list was not a collection of desired traits in a partner but instead a simple archive of toys and things that a young Marceline wrote for Simon to fulfill long ago.

“Oh, it’s just a bunch of toys,” huffed Ice King, “Let’s see….spinny top, a friend for Hambo, puzzle cube, My Little Pony DVDs….”

The mad king’s eyes grew wide as a snaggle-toothed grin encompassed his face, “My Little Pony, I’m sure there’s some material I could use to spice up my latest line of Fionna and Cake fan fiction!”

“Gunther!” called Ice King, “Get daddy’s DVD box and CD player!”

Fionna sighed as she ran her fingers through her long blonde hair as she examined her reflection in the bathroom mirror.

“I think I’m gonna cut my hair,” she said, finally breaking the silence.

“Cake, I’m going to cut my hair!” called Fionna.

“What!?” replied another voice, which quickly revealed to be Cake’s. Who had appeared from the bedroom, still tending to her hair curlers in her fur.

“Why in the world would you cut your beautiful hair!? It’s gorgeous!” exclaimed Cake.

“I just think I need a new look…” murmured Fionna.

“Baby, you wear the same hat, shirt, and skirt like every day….I know! Let’s go clothes shopping!” beamed Cake as she quickly walked over to the bathroom mirror.

“New clothes?” Fionna asked hesitantly.

Cake nod, stretching up toward the mirror as she looks into her reflection, “Yeah, girl, you need a new look to spice things up! I mean, you’re not Marshal Lee. It’s not like you’re immortal with all the time in the world. You need to live it up a little!”

“Mmm…” Fionna hummed, “Well, it wouldn’t hurt to look…” relented the human.

“Sweet babies!” gasped Cake, “I’ll go get a burlap sack and a bunch of treasure from the treasure room!” Cake said as she quickly plucked the curlers from her hur before stamping out in the room.

Fionna sighed slowly, putting her classic hat on as she gazed upon her reflection again, “I like my look; it’s recognizable. I need to be recognizable. I’m Ooo’s local hero!” huffed Fionna.

Fionna would later meet her companion outside after collecting herself. Brushing her hair, teeth and gathering her weapons. Seeming unsure about Cake’s insistence on updating the human’s look.

“Cake, I’m not so sure about this whole ‘updating my look’ thing. I think I’m just going to stick with my look.”

Cake rolled her eyes as she walked over to Fionna. Stretching her arm out before slipping her paw into Fionna’s backpack and pulling out a telephone, quickly dialing it, “Trust me, honey, there’s nothing wrong with just window shopping besides, girl, it’ll be fun!”

Fionna let out a long sigh before crossing her arms impatiently, listening closely to the phone’s dial tone before, moments later, a voice breaks through the receiver.

A booming thundering voice echo’s from the other side, “안녕하십니까?”

“Hey sugar, me and Fionna are looking for a ride into the Crystal Dimension.”

“안녕 예쁜이! 피오나를 데려가도 안전한가요?”

“Yes, yes, I’m sure, so can we go to the Crystal Dimension?”

“확신하는.”

“Awesome,” chuckled Cake, “We’re outside my house.”

Cake quickly stuffed the telephone back into Fionna’s backpack before looking up at the human, “Lord Monochromicorn is taking us to the Crystal Dimension so I can show you some high-end Monochromicorn fashion.”

“Sweet-wait, don’t Monochromicorn’s eat humans, man!?” panicked Fionna.

Cake scoffed, “Just say you’re not human! Most people think humans are extinct anyway!...No offense.”

Fionna rolled her eyes, “None taken.”

The clouds above would turn a dark grey as a thundering crack echoed throughout the land. As Lord Monochromicorn appears before the heroes.

Cake quickly stretched up to the Monochromicornn before giving the stallion creature a tight squeeze, “Hey handsome~ Thanks for coming by.”

Lord Monochromicorn blushed as he bashfully rests his head against Cake before clearing his throat, “갈 준비가 되셨습니까?”

Cake promptly turns to Fionna, “Ready to go, Fionna?”

The human lazily raised a thumbs up at her sister before watching Lord Monochromicorn fire a magical laser from his horn in front of the human, summoning a dark grey portal. Before the three entered the portal.

A massive labyrinth of a city greeted the group as towers of grey, white, and black crystals lined the city streets as bustling cars clogged the roads. As Monochromicorns and cats walked along the winding city sidewalks.

Fionna gazed with wonder as she scrambled to get the words out of her mouth, “Woah, the Crystal Dimension is a metropolis?”

“Should’ve come with us on Charlie’s b-day sis.” shrugged Cake.

Fionna shrugged back in reply, “I dunno, man, I don’t know how to have a relationship with my Cat-Monochromicorn nieces and nephews.”

Cake nervously chuckled, “You and me both….”

“이것에 대해서는 나중에 이야기합시다.”

Cake slowly nod, quickly pointing out the nearby department store to change the subject, “Uh…hey, look at that clothing store!”

“And magical wares!” shouted Fionna, Awe yeah!”

“Babe, we’re gonna skedaddle. Do you want to come with me?”

Lord Monochromicorn yawns before giving a kiss on Cake’s head, “난 집에 갈거야. 필요한 것이 있으면 전화하세요.”

Cake sighed, “Awww…well, we’ll call you when we’re ready to get back. Tell TV I said hi.” waving goodbye as Lord Monochromicorn slipped through the portal and disappeared soon after.

“C’mon, let’s look inside!” exclaimed Fionna as she quickly sprinted inside the shop.

An extensive collection of feminine dresses and attire lined across the room, creating a corridor of cloth and fabrics that foraged a path around the store. Sitting at the far end of the building was a large desk made of crystal, with a large gray cat sitting behind the counter, idly playing with a loose piece of string.

A large swath of potions, elixirs, and charmed/spelled items sat on a set of bookshelves behind the rugged old cat. With Fionna quickly noticed the possibly explosive and deadly magic available to her. The young human leaped forward gracefully, landing on her feet before rapidly pounding her fists against the counter.

“Give me all your cursed junk, man!!!” demanded Fionna.

The cat paused, slowly looking up from his string as he revealed his aged and worn face, “W-wuh?” he grumbled.

“Cursed junk, potions, swords, weapons, charms.” chanted Fionna.

The cat paused before looking back at his bookshelves of ‘magic wares.’ “Oooh…these are perfumes and regular jewelry…. didn’t you read the sign right?”

The human slumped over on the counter defeatedly before loudly sighing, “Cake, this sucks.”

“Fionna, we can get cursed junk any other day. Let’s just get you a new dress,” smirked Cake, lifting a large velvet dressfrom a clothes rack.

The shop door swung open as a pair of well-dressed black cats entered the shop, “Excuse me, are you Fionna and Cake?” inquired the first cat.

“Oh yeah, sup.” greeted Fionna.

“The President wishes to speak to you.” informed the second cat.

“Oh my goodness, The President!?” gasped Cake.

“Yes…like we just said...” replied the first cat.

The group would soon arrive at the Presidental Palace, the cornerstone of Monochromicorn artisan and craftsmanship. With pillars of arching grey crystal shards and pillars of pure white gems holding up this monument to Monochromicorn civil society.

“Wow, real pretty.” whistled Fionna.

“Why does the president need a palace? Shouldn’t a servant of the people not be elevated to that of royalty?” interjected Cake, giving the over-indulgent building much scrutiny.

“I dunno, man. I fight bad guys with my fists and kicks, not through political mumbo jumbo.” shrugged Fiona.

Cake sighed as she shook her head, “Fionna, one of these days, you really need to invest yourself in the world around you, man.”

“I’m fourteen…I think. Just let me fight stuff, and you do the insightful political commentary.” Fionna grinned, giving Cake an amused huff.

Cake rolled her eyes, “Fionna, do you really think the president of this dimension is just gonna throw a big monster at us to fight?”

Fionna could only give a lame shrug to her companion as she rested her arms behind her head. Allowing the cats from earlier to escort the pair through the dazzling halls of the palace.

Fionna examined the castle in a rare moment of consciousness, taking a moment to see the many portraits of the former Presidents of the Crystal Dimension. Before stepping through a set of large chamber doors.

A small Crystal Man sits idly at his desk, seeming to stare blankly at a set of papers with an unexpressive and quite literal blank expression on his face.

The man slowly looks up, “Oh, great, you’re here. Please sit down on those crystal chairs.”

“I'm The President btw. Look, I need you two to help watch over a top-secret Crystal People-Cat-Monochromicorn joint effort to open an uninhabited dimension so we can put more suburbs and apartments in.” explained The President.

“That’s bunk.” huffed Cake, crossing her arms.

“Oh…you didn’t vote for me, didn’t you?”

“No…but mostly because I wasn’t here for the election….also, I live in Ooo most of the time, actually.” shrugged Cake.

“Uh huh…” nodded The President, “Anyway, will you help us? We’ll like pay you and junk, but you’ll have to sign a non-disclosure agreement…also we aren’t responsible if you die.”

“Sure.”

“Whatev’s.”

“Awesome.” mused The President as he quickly slid a set of papers for the heroes to sign, “Sign here, here, and here.”

After signing, the room suddenly shifted as if the entire area was an elevator shaft moving downward. Causing everyone and everything to shift suddenly. The once-lavish exterior quickly changed to dull steel walls with harsh lights illuminating the descent down.

The room was placed on a large platform before slipping into place as a loud, dull thud echoed throughout the room. A large fluorescent lights sparked to life, revealing a massive laboratory with hundreds of scientists hurrying around dozens of machines whirring loudly.

A Crystal Woman would approach the group, “Mr. President, we are prepared for a dimensional tear. Shall we proceed?”

“Yes, doctor, everyone put on your health and safety goggles!” ordered The President.

Once everyone’s goggles were in place, the teams of scientists promptly activated the dozens of machines surrounding a large metallic ring.

“Setting target on potential dimension candidate!” shouted a cat scientist.

“전원 안정화!” replied a Monochromicorn.

“Activating dimension merge!” announced a Crystal scientist.

A bright purple electrical surge encompassed all the machinery for a moment before the delicate technology began to whir and blare loudly, with emergency systems and alarms loudly droning on.

“That can’t be good,” Fionna said bluntly.

“We’re losing stabilization!” screamed a cat.

“I don’t want to die!” shrieked a Crystal Man before promptly running toward the lift.

“No! You’re supposed to handle this and maybe die! I’m the president, for Pete’s sake!” stamped The President.

“Everyone! Take refuge in my body!” ordered Cake, quickly growing ginormous before sheltering everyone from the electrical surge. The large metal ring began to have a strange purple essence encompassing the inner circle. Before, a large explosion suddenly rang out.

A large cloud of smoke hung in the laboratory before slowly clearing out, revealing the now demolished lab and a strange purple Monochromicorn with a smaller and far less elongated body amidst the smog.

“Okay, everybody, it’s safe!” Cake said as she quickly shrunk back down to her normal size.

A cat scientist quickly noticed the unicorn, “Did we fire up the cloning machine again?”

The President shook his head, “Nah, I had it destroyed. Apparently, it’s unconstitutional to clone yourself so you can have a third and fourth term.”

The unicorn appeared dazed and confused, her mane in a blue and purple frizz, “Where am I?... Spike?”

“Hold it, citizen,” pressed The President, “I’m gonna need to see some identification and preferably some taxable income.”

“This is why I’m a sovereign citizen.” hmpfed Cake.

Fionna cautiously raised her hand up, “Guys, I’m pretty sure she’s not from around here.”

“Shoot,” tsk’d The President, “Is your world uninhabited?”

Twilight paused, “My world?... I don’t understand; where am I?”

“You’re in a secret underground lab,” answered Cake.

“The Crystal Dimension.” replied a scientist.

“Somewhere in Ooo…probably.” shrugged Fionna.

The unicorn slowly examined her surroundings before her legs began to tremble. Her eyes rolled to the back of her skull before the unicorn suddenly collapsed unto the hard metallic floor.

The President scratched his head as he sighed, “Well, she doesn’t look like she has any money, and she can’t vote for me next election. Fionna, Cake, since it’s your job to dispose of this kind of junk, you’re now responsible for her.”

“What!?” exclaimed the sisters.

“Shouldn’t you, like, send her back!?” exclaimed Fionna.

The President shrugged, “Oh, yeah, sure. We’ll get on that, but, just keep her away from the Crystal Dimension for a while. I need to keep a clean nose, so I win my third term.”

“I thought you said it was unconstitutional to run for more than two terms.” squinted Cake.

“It is…. I’m changing the constitution.” replied The President.

“Oh.”

“Yeah…anyway, let’s get you out of here before someone outside the NDA sees.”