I've Grown a Costume on My Soul

by PixelMoon

Rating: teen
Tags: Comedy, Romance, Adventure, Equestria Girls, Sex, Sunset Shimmer, Twilight Sparkle, Main 7 (EqG), Human, Rarity (EqG)
Length: 3296

Twilight casts a spell while going through the mirror portal and is left with terrifying effects.

In order to get more familiar with human world's customs, Twilight decides to visit once more. In an attempt to practice magic while in the that world, she casts a special spell while entering the portal, which keeps her magic inside her body.

She arrives during the Canterlot Halloween Party, where Sunset Shimmer reveals that they're hosting a contest for the "Best Vampire Costume". She decides to enter with her friends... however when the sun goes down she finds out that casting the spell while going through the portal has a nasty side-effect: more Equestrian magic has started seeping through it and has started turning everyone in the school into their costumed characters!

Twilight and the humane six must now track down anyone affected by the spell before they escape and wreak havoc upon the city… While trying to find a way to reverse the spell, and also fighting off their own thirst for blood...

* * *

Story requested by Alphamon_Ouryuken. I'm so sorry it took so long, dude!

Published 2018-01-16 13:00:06 UTC
Last updated 2018-01-16 13:00:06 UTC

A Monstrous Story Indeed

Author's Note

This story was requested from someone so long ago, I don't even think they remember it. I had promised myself I would get to it eventually, so here you go!

Please tell me of any mistakes! (Preferably PM) Thank you!!!!!

And enjoy!

~Pixel

A Monstrous Story Indeed

I've Grown a Costume on My Soul
Written by PixelMoon
~X~X~X~

Twilight zipped through her saddle bags, making sure she didn't forget anything. Book on Canterlot High history, check! Magic reserve spell? Check! Now what else, hm...

"Can't you let me come? I went with you all the other times!" Spike complained.

Twilight only shook her head in response. "Sorry, Spike. But this is just something I've got to do on my own. It's imperative that I do it!"

"Impera? Impe?"

"Important."

Twilight was in the room of the Magic Mirror Portal, while Spike was on his knees begging to come with her. She sighed, knowing it was bribing time.

"Alright, I'll let you stay with Rarity if you stop," she said smugly, which the dragon happily nodded to.

Twilight nodded, while laughing a bit, and waved goodbye. She ran to the portal that had a spiral of pinks through it. Before heading through it however, the alicorn mare quickly cast a spell.

"Princess Twilight? Are you okay?"

Twilight groaned as she forced herself to lift her head. Sunset Shimmer - in human form - was in front of her. The female nodded, and took the hand that Sunset offered her.

"Thanks, Sunset. You really didn't have to meet me at the portal though," Twilight said.

"It's nothing," the fiery haired girl insisted, rubbing the back of her head while blushing a bit.

Sunset's eyes suddenly focused on Twilight's forehead while she gawked. Twilight gave a confused look. "What?" she asked.

"Why, do you have...your...horn?" Sunset paused several times out of sheer confusion. She pointed at the former pony's forehead, which was consumed by a slender horn with spirals swirling through it.

"I cast a spell so I could still have my pony features, such as wings and magic. Now won't you tell me of why your wearing that costume?"

Sunset glanced down and saw she was still wearing the vampire costume Rarity had fitted for her. "Long story. I can tell you on our way to Rarity's if you'll like."

Twilight nodded, while Sunset began. While she was talking, the former pony dazed off, flying off multiple times, watching items levitated through the air as she tested her magic.

~X~X~X~

"-So yeah. Rarity was fitting me for the Halloween dance tonight basically. And we wanted you to come. Now that you have your magic, it should be a great costume!" Sunset finished.

Twilight nodded as the pair reached their destination. It was Rarity's Boutique, and inside she could see Rarity adjusting a costume on Rainbow Dash.

As they entered the shop, the two Equines heard part of Rarity and Dash's conversation.

"-Hurry up, Rarity! I want to be one of the first people there!" Rainbow Dash exclaimed.

"Hush, Rainbow Dash! The more you move, the less this will look like a vampire!" Rarity murmured, her gaze focused on Dash's costume.

The belle of the shop chimed, catching the seamstress's attention. She glanced up from her work, but abandoned it completely when she saw who it was.

"Oh Twilight! You're here! Thanks Sunset, oh and I just love your costume! I wonder who made it!" Rarity gave a wink at Sunset, who rolled her eyes but smiled in return. Twilight waved at the replica of her Ponyville fashionista friend.

"Hey Rarity. How are you doing?" Twilight greeted.

"Oh just fine, thanks for asking. I just wish somebody would cooperate with me," she replied, sending daggers at Rainbow Dash, who shrugged her arms in response.

Sunset and Twilight giggled. Rarity then grabbed the ponifed Twilight and put her in a chair. "Give me a minute, darling. Then I can give you the most amazing costume for you ever!"

Twilight shook her head. "Oh no, Rarity. I couldn't possibly ask you to do that. Besides, I have my magic this time around, so I should be able to conjure a costume myself."

Rarity stared at Twilight, only now noticing the horn sticking out of her forehead. She shook her head non the less. "Please, darling! Magic can't get you everywhere in life! At least let me do part of it!"

Twilight sighed in defeat. "Fine."

Rarity squealed in delight. She quickly finished Rainbow's costume with a few groans from the latter and then started Twilight's. The former alicorn had made the main part of the costume, and allowed Rarity to make the vampire part of it and the effects, alongside her hair style.

After a while, the seamstress soon finished the costume for the princess. Twilight had her hair curled in a sexy way, as Rarity insisted. She had blood red eyes via magic and a paled face via magic as well. Her wings had transformed into bat wings, a spell that Twilight had learned not long after the Flutterbat issue. Her actual costume consisted of black and red colors, and was a cape with a short cut dress, just barely hiding her pussy. The look had been completed with black high heels to match.

Twilight felt very exposed and uncomfortable. She felt her pussy twitch underneath the fabric. "Uh, Rarity? Are you sure this is really appropriate for a school dance..."

Rarity only dismissed the thought with a flick of her hand. "Nonsense, darling! You look positively smashing! The boys will be chasing you all evening!" Besides, you look sexy as fuck...

The fashionista suddenly felt heat in her cheeks and her own pussy. She coughed politely and shook her head to rid the thought from existence. At least for the time being, anyway.

"So, are we ready to go?" Sunset asked.

"Hold on! Just let me get my costume on and we can go," Rarity replied. She quickly put eye-shadow on Twilight and then did her own makeup. She then slid her costume on her slender body.

When she was done, Rarity looked more like a prissy goth person than a vampire. It still looked good non the less.

"Alright, let's go," Rarity said. With that, the trio left the boutique to meet their friends up at the dance.

~X~X~X~

The three people reached the dance. There, their friends Rainbow Dash; whom left after her costume was done, Applejack, Pinkie Pie, and Fluttershy were waiting at the front of the school. Applejack stared at Twilight with an impressed look.

"Whoa, Twilight. Color me impressed. You look damn sexy with that costume," Applejack complimented.

Twilight blushed and suddenly felt exposed once more. "Heh, thanks AJ."

The group of friends walked into the school and to the dance. Twilight glanced back at her way home, and for a spilt second she could've sworn she saw Equestrian magic buzz around it. Curiosity got the better of the former pony, and she turned to inspect it but got stopped by Sunset Shimmer.

"You coming?" she asked.

Twilight nodded and walked into the school, leaving what she assumed as just her imagination. Little did she know, she was correct. Magic bubbled out of the portal and flew into the sun that was close to the horizon.

Inside the gym of the school, everyone that attended Canterlot High was partying to the latest songs. Laughter filled the room, giddiness filling Twilight.

Her friends and herself found a corner to themselves. Pinkie and Fluttershy went off to get drinks, and Rainbow Dasha ne Applejack engaged in a thumb wrestle. Sunset, Rarity, and Twilight danced around.

At least, Twilight thought she was dancing around. But Rarity told her that she was doing it wrong. So then while Sunset danced, Rarity lectured the former alicorn how to dance properly.

She had just managed to get the hang of it when Fluttershy returned with drinks. Pinkie Pie, on the other hand, was nowhere to be seen.

"Where's Pinkie at?" Rainbow asked. Applejack grumbled at the winner of their thumb wrestle but nodded in agreement.

"She's still at the snack table getting cupcakes. Lots of them, might I add," Fluttershy said while giggling.

Twilight facepalmed. "Of course she is."

Suddenly a sound of a finger tapping a mic ran throughout the gym. The music stopped playing and everybody turned to the stage to see Principal Celestia with Vice-Principal Luna.

"Hello, everybody! I hope you all are having a fantastic night!" Celestia exclaimed. Everybody in the gym cheered, indicating that everyone was having fun. "Well, it's about to get better! Anybody who wants to join the vampire costume contest come up to the stage and the judges; Vice-Principal Luna and myself, will pick who wins!"

At the same time, several people with vampire costumes on; including Twilight, Rarity, Sunset, and Rainbow Dash, ran to the stage. Pinkie, Applejack, and Fluttershy stayed back. Pinkie had on a disco roller skating costume, complete with her hair in frizzy buns and a purple lightning bolt on her face. Applejack was a lion, and Fluttershy wore a black
Masquerade dress, but without the mask.

The line near the stage was getting shorter, and it was soon Rarity's turn. She strutted on the stage as if it was a runway, posing at random times. Her costume earned ohs amd ahs from the crowd below her.

When she finally got off the stage, Twilight walked onto the stage next. She closed her eyes and walked proudly, her head in the air. Rarity gave a look of envy at her Equine friend's years of practice of being princessy

The judges stared with impressive stares at Twilight's costume. She opened her eyes, revealing blood red eyes. She hissed loudly, the fangs in her mouth glinting in the lighting.

Celestia clapped her hands. Twilight got off the stage and allowed the other people in line to go. Rarity raved to Twilight over how good she did, who dismissed it with humidity.

The two chatted quietly as they watched Rainbow on the stage. There conversation had engaged Twilight's life in Equestria, along with Rarity's latest fashions.

After Rainbow was done and joined Rarity and Twilight, it was Sunset's turn on stage. They all watched and talked until she was done. They then walked back to their other friends.

"Wow, Twilight. If I didn't know any better, I'd say you were a real vampire!" Pinkie exclaimed with an impressed look on her face.

Twilight blushed and rubbed the back of her neck. "Hehe, thanks Pinkie. I bet those boys in line enjoyed their view though."

Her friends giggled in response, a blush seeping into their skins. After a few seconds they begun dancing again as they waited for the contest results.

Eventually the last person made their way off stage, and Celestia and Luna talked quietly for a few minutes. After the two seemed to come to an agreement, they made their way onto the stage with a box, assummingly the reward.

Celestia tapped the mic again, gaining everyone's attention once more. "Okay, everybody! After some discussion, myself and Vice-Principal Luna have come to an agreement for the best vampire costume!"

Everyone cheered. Once it was quiet again, Celestia continued. "The winner of the Vampire Costume Contest is..."

Suddenly, Twilight felt a change go through her. She didn't know what it was, or if anyone else felt it. She felt a little dreary for a second, before feeling a bit thirsty. She glanced at Rarity, who seemed to have the same feeling.

One thing was different though. Well, she she should say a few things. For one thing, everyone had stopped talking, including Celestia, who was dressed as a mouse. Rarity's eyes were turning a deep blood red, and she saw the fangs on Rarity grow sharper. She felt her own fangs become incredibly sharp as well, and her eyesight seemed a lot better too.

She glanced at her other friends, who seemed a bit overwhelmed. Applejack seemed to be growing hunger, and was staring at Fluttershy wantingly. Twilight stared at Fluttershy as well, and found herself staring hungrily at her neck. After a few seconds, she heard a growl ring throughout the room.

Suddenly, everybody in the room became either a monster, mental, crazy, or someone from a movie or fairytale. Twilight flew up with her bat wings with hunger. She stared at Luna, who was dressed as dog. She barked with fear of what was happening, and had fur growing on her body.

Twilight watched as Luna's body rearranged itself. She was forced to the ground on all fours, and her head snapped up and into the place of a dog with a loud sick crack. She grew a tail, and Twilight could tell she was losing her mind and voice.

Luna gave one last human screech before she lost her voice and began helplessly yelping. She felt her mind shatter as she found a new meaning in life.

What was left of Luna was lost and in her place was a puppy that was the first victim of Twilight Sparkle. Twilight dove down to the oblivious dog, dodging people along the way.

Twilight slammed onto the stage, and took on a better shape. She used her horn and transformed into an alicorn against but still wore the dress that still fit around her pony body, and was still arguably sexy.

She lowered her head to the Luna dog, and just as she was about to drink her blood, a yellow blur flung into her. Twilight hissed loudly at the figure who dared interrupt her meal.

The figure had a black dress on, and a Masquerade Mask had appeared on her face. It seemed she couldn't get it off, proven by the fact of who was wearing it.

"Twilight! You have to snap out of it! Something is happening! Everyone is turning into what they dressed as! And kW I can't get this mask off, oh I'm so scared! Please, Twilight!" Fluttershy pleaded.

Twilight stared at Fluttershy, but stayed a vampire. Suddenly, a pony version of Fluttershy appeared in her mind. She shook her head before falling to the ground.

She muttered a few words, the vampirism attempting to overtake her mind. Twilight suddenly screamed out no, and then stared at Fluttershy.

She offered a hoof to Fluttershy, accepted it. She stood on her knees to talk to the pony Twilight. "Would you rather have me as a human like you?" Twilight asked. Fluttershy gingerly nodded.

Twilight's horn glowed and she became a human after a flash. She bagan running to her other friends, which had a now real lion Applejack, a Pinkie freaking out; who seemed unchanged, and the vampiric Rarity, Rainbow Dash, and Sunset Shimmer.

It seemed that Sunset was fighting it. She must've seen what happened to Twilight, and was vague to what was happening. Rainbow Dash was somewhat fighting it. She was trying to resist, but was failing to do so. Rarity, on the other hand, was going crazy and was screaming blood.

Fluttershy headed for Rainbow Dash. As her oldest friend, she might be able to get through her thick skull. Twilight went to Sunset Shimmer ands suddenly caught a whiff of blood.

She trailed off her path for a spilt second, before slapping herself in the face. "Dammit, Twilight! You have to stay strong! It's imperative!"

She continued to run to Sunset. Once there, she quickly cast a spell on the Equine. Sunset struggled with her vampirism, but after a minute returned to her normal self.

"Ugh... Twilight? What in Tartarus happened?" Sunset groaned.

"There's really no time, Sunset. It seems everybody turned into what they are dressed as. I almost ate Luna, but Fluttershy stopped me. I think this might be happening because of the magic here. But our goal right now is to save everybody. Once I do that, if I leave this world, magic won't be here, and thus this shouldn't happen. I guess I shouldn't have kept my horn," Twilight explained.

Sunset patted her back and mentally slapping herself for staring at Twilight's neck the whole time. The two went over to Rarity to try and save her.

Rarity jumped onto Sunset, but blasted back by Twilight's magic. Rarity stared at Twilight, spit falling down her lips.

"Whoa, miss sexy. How are you doing? Why don't you come over here and let me just bite you, and we can sleep together..." Rarity murmured, inching closer to Twilight once she got up. "A hot bitch like you should have a proper fucktoy. And let that be me."

Twilight gave an amused smile. "I have some things to talk to her about once we are done here," she stated before slapped Rarity in the face.

Rarity hissed in pain and dove for Twilight. The former alicorn merely dodged the attack and quickly cast a spell on Rarity, sending her to the ground.

Rarity tried to get up, but Twilight pressed her body against her. The vampire struggled underneath Twilight's grasp, gut stopped when Twilight lowered her head to Rarity's face.

Sunset watched with confusion as Twilight inched closer to Rarity. She didn't think that she was going to suck her blood; she didn't look thirsty at all. The Equine figure watched with amazement as Twilight pressed her lips against Rarity's, bringing her back from her vampiric state.

The two held the kiss for a few seconds, before Twilight let go and got off of Rarity. Sunset watched as Rarity gave a blank stare of confusion, happiness, and lust.

"T-twilight! Did you just kiss me!?" Rarity exclaimed with fake horror.

Twilight nodded. "It was the only way to bring you back. Your pony counterpart is a unicorn, so you were able to react to my magic."

Rarity nodded and quickly turned her gaze away. Fluttershy and Rainbow Dash lay together on the floor, with rainbow on top. It seemed like she was sucking her blood.

Wait, Rainbow Dash was drinking Fluttershy?!

"Twilight! I think we have a problem!" Rarity pointed to Dash and Fluttershy. Twilight gave a look of absolute horror as one of her friend's life got sucked out of her.

"No!" Twilight shouted, quickly flying over to Rainbow and knocking her off Fluttershy. Rainbow hissed and tried to fling herself onto the other vampire, but the Equine flew higher up and out of reach.

Rainbow hissed and tried to jump up to grab Twilight, only to get hit with a laser beam. She groaned before passing out.

Twilight blinked. "Well that could have gone better."

Suddenly she heard a scream she knew all too well. Pinkie Pie was in a corner, trapped by the lion Applejack. Twilight sighed before lazily lighting her horn and shooting the lion.

Applejack immediately got flung onto the ground. She had passed out for the time being, which Twilight just shrugged to.

"They'll wake up later," she said to Sunset.

Twilight flew to the stage and her horn started glowing. Everyone's eyes suddenly focused on her. One by one, everybody's monstrous features melted away, leaving them just wearing a costume.

Everyone cheered for Twilight. The Equine just smiled before partying with her friends again.

Thanks again for inviting me, Sunset, " Twilight said.

She was next to the portal, and Sunset Shimmer was saying goodbye to her friend

"It was nothing. Thanks for saving the school again."

The two laughed and hugged before Twilight went through the portal. After a bunch of random colors, she was in her castle.

Rarity happened to be in there, and so Twilight had to ask her something.

"Oh hey Rarity! I have a question. Do you have a crush on me?"

The End.