The Enemy Within

by KATCompositions


Molecular Modifier

Tap, tap, tap, tap.

Trixie opened her eyes and blinked at the dazzling light above her bed. Her head was aching.

Tap, tap, tap, tap.

She tried to sit up but immediately blacked out and had to lie down again. On inspection, she found her head was wrapped in bandages.

Tap, tap, tap, tap, tap.

A torrent of memories flooded back. She was in a crashed pod, somewhere in the distant future. Was that right? Maybe she'd taken such a knock that she wasn't thinking straight. Anyway, it was impossible to concentrate with that constant tapping going on. She leaned over the side of the bunk. There, relentlessly marching up and down was Twilight Sparkle.

"What are you doing?" said Trixie.

This did not yield any response.

"Twilight, stop pacing,"

"I'm not pacing, am I? Oh yes, so I am, I'm pacing". She reached the window, turned and started the sequence again.

"Is there something wrong?"

"No. Whatever gave you that impression?" said Twilight, "I mean being stranded at the end of the universe, millions of years away from home, with no hope of ever getting back, does tend to have a negative effect on one's general well-being, but other than that I'm fine, absolutely fine". She laughed hysterically.

"Are you missing your friends again?"

"It's not just that. It's this place. How long has it been now, four weeks? Four weeks stuck in here". Twilight was picking up her pace now, her hooves pounding the floor plates with increasing urgency. "Four weeks of the same routine, the same grey walls, the same grey doors, the same grey ceiling, it's enough to drive anypony crazy!"

"So, you're mad because of, the walls?"

Twilight flung herself onto the bottom bunk. "It wouldn't be so bad if there was something to read, or to do around here; some form of stimulation. Anything, and I mean anything, would be better than this,"

Trixie saw an opportunity. "How about a magic show from the great and powerful Trixie?"

"Except that,"

"Oh come on. You are supposed to be my mentor. Besides I've been working on my teleportation spell,"

"Ah, that explains the bandages then,"

"Just a little scrape, that's all. It's so cluttered in that Doctor's laboratory, it's hard to avoid bumping into things,"

"What were you doing in the Doctor's laboratory?"

"Well, that wasn't where I started from. I'm not quite sure how I ended up in there actually. By the way, if he comes asking what happened to his equipment, Derpy was responsible, not me,"

"Sure. Anyway, in case you had forgotten, we're still suffering the effects of your last performance".

Trixie groaned. She hardly needed reminding that it was her attempt at a time spell which had left them stranded millions of years from civilisation in the first place.

"If we ever get back home I'm going to remember that time travel is not something to be messed with". Rolling over, Twilight found a grey wall glaring at her. "Eergh. I can't even stretch my wings in here,"

"Oh please," said Trixie, rolling her eyes, "even Derpy can fly better than you,"

"That's not true," Twilight protested, "and anyway that isn't a fair comparison. She's had wings her whole life; she grew up with them. If you gave Derpy a horn, she wouldn't be able to use magic like I can".

"Well we'll never know, will we? I mean it's not like some device is going to show up that can give her magical powers".

At that point the door was kicked open. Doctor Whooves stood at the entrance, thumping his hooves excitedly.

"Come quickly. I've invented a machine that can turn a pegasus into a unicorn".

"What?" cried Twilight and Trixie, sitting bolt upright in unison.


"You can't change a pegasus into a unicorn just like that," said Twilight, "can you?"

She, Trixie and Derpy were stood on the threshold of the Doctor's laboratory, deep in the belly of the pod. He was busy running around, comparing calculations and making final adjustments to his machine, skillfully managing to not trip on the assorted junk, scattered about on the floor.

"With the molecular modifier you can," he said, "or a unicorn into a pegasus. It tweaks the genetic structure on an atomic level. Think of it like, an apple. With the right preparation it has the potential to become something delicious, like apple pie, except it doesn't really work like that at all. Actually, forget apple pie. Just trust the science".

The molecular modifier, as the Doctor described it, was a tubular construction balanced on a tripod, with the controls at one end and some sort of laser pointer at the other.

Twilight remained sceptical. "Maybe there are some areas where science isn't meant to interfere,"

"Nonsense," the Doctor answered, "science and mathematics are the two things you can always rely on. Without them we'd still be living on wild superstitions, like that one you were on about Derpy, about the Muffin King,"

Derpy gasped. "Do not mock the Muffin King. He hears every word, and one day he shall return".

"You know the difference between science, and superstition?" said the Doctor, "science requires research, and dedication. For example, the alignment of this device has to be precise, otherwise the consequences could be catastrophic".

The tripod toppled over onto the floor.

The Doctor forced a smile, "not again. I keep saying one of these centuries I'll get round to fixing that leg. I think there must be a screw loose,"

"You can say that again," said Trixie.

The Doctor stood up straight, having once more propped up and primed the device. "Now all I need is a volunteer. I'd test it on myself, of course, but somepony has to operate it, and anyway, being an earth pony, it wouldn't have any effect on me theoretically,"

"So, you're proposing that I participate in one of your experiments, and get blown up, or turned into a frog or something," said Trixie, "let me think about it". She stood there, gazing at the ceiling, as if deep in contemplation. "Er, no. The great and powerful Trixie would prefer to stay in one piece".

"Well it can't be me because I'm already an alicorn," Twilight reminded them,

"We know," Trixie groaned,

"In that case, Muffins, you're up," said the Doctor.

All eyes turned to Derpy. She stepped forward, without hesitation, into the range of the molecular modifier.

"Wait, don't tell me you're actually going to put your life in the hooves of this maniac?" said Trixie, "are you really that stupid? Don't answer that,"

"I'm not stupid," Derpy replied, "and I trust the Doctor".


The machine hummed with power, as Doctor Whooves operated the controls. The two spectators looked on anxiously. Derpy, meanwhile, exhibited her usual carefree smile, as if this was all perfectly ordinary.

"I suggest you look away," warned the Doctor.

"Wha-" Twilight started to say, but was cut short by blinding flash. Once her vision had cleared it became obvious that something had gone very wrong.

Derpy noticed that everypony was staring at her with concerned expressions. Even the Doctor seemed agitated.

"What happened?" she asked, "did it work?"

"Well, it, half worked," said Twilight,

"What do you mean?"

"I'm afraid something terrible has happened, something awful, it's so horrifying I can hardly bear to look".

Derpy couldn't understand. She felt fine. Her hooves were working normally; she did a little jig to make sure. She felt her forehead, and found that a horn had grown there. So it had worked then. Everything else was in order. She swished her tail, unfurled her wings and gave them a flutter. Wait, wings? She still had wings.

"I'm an, alicorn?"

The Doctor sensed the concern among the others. "Don't worry," he assured them, "this, is only a temporary phase; the new molecular structure will stabilise any moment now".

They waited. Nothing happened.

"Any moment now," the Doctor said again.

Still nothing.

"I don't understand". He opened up a side panel to make a closer inspection of the inner workings of the molecular modifier. "Great whickering stallions, everything is out of alignment in here. How can that be possible? You know, it's almost as if somepony has been down here tampering with my equipment".

Trixie slowly retreated into the corner while Twilight glared at her.


"Come on, you have to concentrate".

Trixie was sat at a table in the midsection of the pod. The table had a dull metallic texture like the rest of the room and had been similarly cluttered with gadgets, spare cables and odd trinkets. She had cleared these items and now a muffin stood in their place, which Derpy was staring at intently.

"I am trying," she insisted,

"Look, I'll show you," said Trixie. She too began focusing on the muffin. "Total concentration, see. Remember what I said, like you're in a bubble,"

"Ooo I like bubbles," said Derpy, "sometimes I have dreams where I'm floating and there are lots of bubbles and..."

"Derpy," snapped Trixie,

"Oh, sorry,"

"As I was saying, you're in a bubble, an empty bubble, where nothing is going to distract you and... what's that speck on the floor? I've never noticed that before".

There were hoofsteps coming up from the laboratory.

"The Doctor says it could take weeks to get that machine repaired," said Twilight Sparkle, reaching the top of the stairs, "and until then we have no way of changing Derpy back. This is a disaster".

Trixie and Derpy were still fixated on the muffin and neither of them acknowledged her.

"What are you girls doing?"

"I thought Derpy could benefit from this opportunity by learning a few tricks from the best," Trixie explained,

"Well," said Twilight, "It would be my privilege, but... Oh. You mean you". She frowned.

"Right now I'm trying to get her to turn a muffin into a cupcake",

"I think you might have more success if you did it the other way round," she suggested, "anyway, what are we going to do?"

"About what?"

"About this. We have to do something. You can't just have any ordinary pony just become an alicorn, just like that. I mean what's next? Before you know it, they'll be anarchy, chaos and disarray, and, what are you staring at me like that for?" Twilight realised she had involuntarily extended her wings. She quickly folded them away. "That was different," she said, "that was, magic",

"And what's so different about that?" said Trixie,

"It's different because, because, ergh, I'm going to bed. I'll think of a solution to this later".

With that, Twilight disappeared through the door to the bunk room. Trixie and Derpy were left alone once more.

"Now that we have quiet in here, let's have another try shall we? Complete concentration remember," said Trixie.

Derpy stared at the muffin again. After a couple of minutes, nothing had happened.

Trixie shook her head. "Oh come on. Don't you want to become great and powerful, and be the greatest magician in Equestria, like Trixie? I know it takes years of practice to reach my level, for other ponies that is; it all came naturally to me, of course, but you could at least... huh?"

Trixie found herself suspended in a magic bubble. Derpy's horn was glowing. Moments later she was propelled across the room and slammed into the airlock door. She came to rest, dazed and disoriented, in a pile of the Doctor's junk.

"Are you okay, Trixie?" said Derpy,

"Well that was, something," she replied, attempting to stand up, "your technique could maybe use a little more control,"

"I'm sorry. I just don't know what happened".


Twilight rolled over on her bed as Trixie entered the bunk room. She now had bandages on her legs and flank to go with the one around her head.

"Gosh, what happened to you?" asked Twilight,

"Derpy," was her response,

"Oh, did she make any progress with her magic?"

"Well she threw me across the room a few times, but other than that, nothing. It doesn't make sense. You can't fault the teaching; I mean who better to guide her than somepony as skilful with magic as me".

Trixie spotted that a corner of the bottom sheet on her bunk had slipped out from under the mattress. She used her magic to correct it, only for the other corner to pop out instead. She groaned and repeated the spell several times, each time with the same result as before.

"Here, let me help you," said Twilight, getting up,

"I don't require any assistance,"

"I don't mind. I can't sleep anyway".

Twilight stood back and began casting a spell which levitated the pillow, sheets and mattress from the top bunk separately, allowing her to fold the corners under all at once.

"It's this whole Derpy thing," she said, yawning, "the Doctor's gone too far this time. He's messing with things he doesn't understand,"

"Oh I get it now," said Trixie,

"Get what?"

"I should have seen it before. It's obvious isn't it?"

"What is?"

Trixie cleared her throat. "You don't want Derpy to be an alicorn because it means you're no longer special,"

"Actually, that has nothing to do with it". Having finished admiring her work, Twilight went back to her bed.

"Anypony could become princess of friendship you know, it's not that hard. It could have been me with the right opportunities,"

Twilight had to contain herself from bursting out laughing. "You, princess of friendship? You?"

"And what's so strange about that?"

"Well, for a start the princess of friendship should have, friends".

Trixie looked offended. "You say that almost as if I don't have friends".

"Okay, name some,"

"Obviously I can't think of every friend I've ever had on the spot,"

"Name one,"

"Oh, as many as that?" Trixie thought for a moment. "Twilight Sparkle," she said, giving her best cheesy smile.

"You'll have to do better than that,"

"Okay, so maybe I don't have many friends," she admitted, "but you don't need loads of friends to be a good friend,"

"Okay then, in what way have you been a good friend?"

After deliberating on this for some time, Trixie said "I sent you a card on your birthday".

"Yeah, a Hearts and Hooves card," Twilight sighed,

Trixie blushed. "Oh, was it? I must have mixed them up,"

"And not only that; you spelt my name wrong. There is no L-I-T-E in Twilight. I mean, how could you even do such a thing? It makes me sick". She breathed heavily.

"You have problems, you know that, right?"

It was then that Trixie's blanket departed from her. It didn't levitate so much as drift into the air, like it was weightless. "You've already done a great job with the bed; you can leave it alone now".

"I'm not doing this," Twilight replied. She tried to grab hold of her own errant blanket, only to find that she was now floating as well. Glancing around, she saw bubbles spurting up from the floor, while fish swam across the room. This gave her an idea.

"What in the name of Celestia is going on here?" cried Trixie, spiralling through the air, her hooves flailing in all directions. A group of fish darted out of the way and she realised she was on a head-on collision course with the wall. "Not again". She closed her eyes.

But instead of the anticipated impact, she felt a warm, soft sensation. She opened her eyes and found Twilight holding onto her. Trixie smiled.

"Swim," Twilight ordered,

"Where?"

"We need to get to the laboratory, and find out if the Doctor knows anything".