"Hold on." Twilight scribbled down a note on her clipboard. "So your hair...can transform you into anything you want?"

"Well, not everything. It's not like I can shapeshift with it or anything. I just use it to change outfits." Sunset chuckled. "You know I haven't had to wash my clothes in months?"

Twilight visibly backed her office chair, and herself, away, a hesitant look on her features.

"I said I haven't had to wash my clothes in months. Not that I haven't washed them at all." Sunset crossed her arms. "Anyway, what exactly are you planning on doing?"

"If your hair is able to do that in this world, then it might be Equestrian magic. No, scratch that. It's definitely Equestrian magic." Tapping her pencil on the top of the clipboard, Twilight took a moment to think. Then, she looked up at Sunset. "Do it again."

With an astounding amount of incredulity: "...Here?"

And with a heavy dose of dry sarcasm in return: "No, on the moon."

Sunset looked around at all of the equipment surrounding her. "Are you sure? 'Cause I really don't want to break anything."

"Just do it!"

"Okay, okay!"

Taking a deep breath, Sunset began to float into the air, a rather holy glow surrounding her body. Her hair began flowing out in waves behind her the more she rose, until finally, her body stopped at a point in midair. Her hair began flowing only slightly outwards, then it suddenly shot out to the sides. As Sunset curled up into the fetal position, her hair folded back into itself, taking the form of its owner with it and trapping her in a cocoon of red and yellow. After a few seconds -- ten to be exact, as Twilight noted -- the cocoon opened to reveal Sunset in a rather gaudy-looking green dress, her hair flowing behind her in a breeze unknown. She slowly uncurled herself and floated back to the ground, only opening her eyes when she felt her feet hit earth.

The feat was met with silence. Twilight's jaw was slack, her eyes wide as she simply stared at Sunset with awe. Sunset, in contrast, looked more confused than anything else, because surely there were about twenty-or-so other feats she and the rest of the girls had seen and experienced that outclassed something as simple as prehensile hair transformation.

Or maybe it was the dress. It looked like the one a bridesmaid would wear to a wedding to not stand out from the bride. Sunset hated it.

"You need me to do it again?" she asked hopefully.

Twilight blinked and closed her jaw. "Huh? I- oh. N-no, you don't have to. I'm..." She rubbed her forehead. "I'm sorry, I'm just in shock. How long have you been able to do this?"

"Since fillyhood. I just tend to do it in private."

"And you never told me? Or anyone else?"

"No."

Reviewing her notes again, Twilight squinted. "Wait. So if you use it for changing outfits here, what did you use it for in Equestria?"

Sunset bit her lower lip. She didn't say anything for a few moments. Twilight leaned forward expectantly, raising an eyebrow in an "I'm waiting" sort of gesture.

"M-many things," Sunset started. "For one, it gave me wings-"

"It what."

"Not actual wings! They were illusory ones. Something to show off to other ponies, but not anything that could be used for flight. Celestia caught me before I could do any showing-off, though, and when she asked me how I did it, I lied and said it was just a spell I read in a book."

Going by her expression, it was easy to tell that Twilight wasn't quite sure how to take in that information. "Okay," she responded hesitantly. "What else?"

"I could also use it to give me outfits. Came in handy whenever I had to attend fancy parties and meetings as the princess's personal student." Remembering how droll said parties and meetings were made Sunset roll her eyes. "Though I also use it here, obviously."

"...You do know Rarity is more than happy to stitch you up anything you need?"

"Yeah. Which is why I didn't tell her. I can feel the preemptive jealousy wafting off of her from where I'm standing."

"She could probably do that with her long hair. And I mean long. Hair. Longer than the span of this entire room. I measured."

"But does she have the magic to pull it off?" Sunset smirked. "No. Besides, doing what I do would be the easy way out for her. She likes making clothes."

Twilight opened her mouth to object, stopped as she thought about Sunset's words, then closed her mouth and nodded. "Okay. Fair point. Moving on. So what else can your hair power do?"

"Protection. Putting myself in a cocoon makes a better shield than you'd think." As she gently ran her fingers through a section of her hair, Sunset straightened. "Especially since my hair is thick. Genetics tipped the scale in my favor."

"Tone down the ego there." Twilight's gaze moved to Sunset's geode. "Is all this tied to your geode somehow?"

Sunset put on a look of confusion. "No. My power is touch empathy. This hair ability is something different." she said. "Though if you want to run tests and see if the two are connected, be my guest."

Clasping her hands and bowing her head down, Twilight became deep in thought. Sunset, meanwhile, killed time by eyeing her dress and wondering if there was at least one nice thing she could say about it.

"No." Twilight raised her head after a few minutes and stared at Sunset with burning intent. "The legitimacy of your words holds weight. This has nothing to do with your geode. It's something else." She stood up. "Can you contact the other Twilight? See if she can do this too?"

Sunset hesitated for a moment. "I could, but she hasn't wrote back in a while. If she actually does have prehensile hair, though, you'd think she'd tell me."

"Fair point. Well, if we can't contact the other Twilight, then I have an idea in the meantime."

As Twilight turned towards her desk, seemingly looking for something important, Sunset watched. The dress began to itch a little bit, and she scratched her arm idly. Her focus was too much on Twilight to worry about what she was wearing.

"Aha! Here it is." Twilight, with a delighted grin on her face, held up a small test tube. "Now, I need a hair sample."

"I- what?"

Before Sunset could protest, Twilight took a few steps towards her and let her fingers wrap around an individual strand of hair, then plucked it with such ferocity that it made Sunset verbally react in pain with an "oww" and a more emotional "why did you do that?"

Twilight slipped the hair into the test tube. "Thank you. This will help tremendously."

Wiping the tears away that began to form at the corner of her right eye, Sunset sighed. "You're welcome. Now, you sure you don't want to get out of the house and go to the mall with me?"

"Normally I'd say yes, but Sunset," Twilight sat in her chair and spun around, "this could be huge. Not just for our world, but for Equestria as well. I need to do all the research I can about this."

It wasn't hard to spot Twilight biting her own index finger. "You're jealous, aren't you?"

"Very."

"I'll leave now."

"Please do, before I take more than just a single strand of hair."

The telltale five-rap knock made Luna heave a sigh. "What is it, sister?"

"Luna, we're leaving for the atrium in ten minutes. And when I say we're leaving, I mean it this time. Whether you're finished getting ready or not."

"I am simply putting on some final touches. Do bear with me."

As Luna's gaze drifted to the torn and battered dress that laid on her bed, she frowned, knowing that circumstances had forced her hoof to do something she wasn't all too keen on doing. But it wasn't like she could go to the dinner party with nothing on while her sister was, without a doubt, wearing something elaborately regal.

Her horn became encased in illustrious blue magic, which wrapped around her entire body in turn. Slowly she floated upwards before stopping in midair, feeling her ever-waving hair extend and wrap her in a cozy cocoon of the night sky. The sensation of feeling covered encased her body, and before she knew it, she was released and was floating towards the ground again.

A quick look in the mirror showed that her dress was nearly identical to the one on her bed, only with a few pearls around the train for accent. With so little time, it wasn't like she could be picky, anyhow.

"Ah, there you are." Celestia smiled warmly as Luna slipped out of the room and closed the door behind her, "For a moment, I was afraid you'd fallen in."

"From what I understand, Tia, that joke does not work in any room besides the lavatory."

Celestia began walking, Luna keeping a steady pace next to her. "Mm. Well, anyway, I trust that instant costume change spell has been serving you well?"

"The-" Luna faltered. "How did you..."

"It takes you forever to put on a dress, Lulu. And believe me, I've timed it."

Luna gave an irritated nicker. "Touche. But I do not use it often. It is merely a shortcut that puts fashion designers out of business."

Just as Celestia was about to respond, a panicked palace guard rushed up to the princess pair. "Er- um, p-pardon me, Your Highnesses, I understand you're in a rush but Princess Twilight just sent me a letter and it's on a rather urgent manner!"

Both sisters shared looks of confusion. Celestia held out her hoof. "Please, if you would give me the letter?"

The guard complied, placing the letter in Celestia's hoof before moving to her right side and walking alongside her. She opened the scroll and read the letter aloud.

Dear Princess Celestia,
Recently I came across a rather interesting spell known as the "instant costume change" spell. It allows the user to let themselves be wrapped up in their mane and tail, producing an outfit that is made according to their thoughts. Seeing the potential use in such a spell, I decided to give it a whirl. I mean, it looks easy enough, right?

Well, it wasn't. My mane and tail are now eldritch abominations that have spread out of the castle and seeped into Ponyville. I've lost track of how many ponies it's captured.

Normally I wouldn't bother you for something like this, but I'm afraid this is a little too out of my depth- hey, get your...uh...whatever off of Spike! Ugh...well, it's too late now. Just as long as he doesn't have to write upside down.

Please send help immediately!

From,
Twilight Sparkle

P.S.: Rarity keeps telling me "I told you so". My mane seems to be swallowing her more and more every time she repeats it. Please help!

Now it was Celestia's turn to falter in her gait. "Twilight knows that spell?"

"I would not be so surprised, Tia. You know how new spells fascinate her. Even more so if they appear to be easy ones." Luna shook her head. "I suppose I shall be attending the dinner party without a plus one?"

Celestia gave a nod to Luna, then let her gaze land on the guard. "Thank you. Please escort Luna to the dinner party in my stead."

"Of course, Princess."

As Celestia took off, there was only one intrusive thought circulating in her mind.

Stars forbid if Twilight uses that spell to give herself another pair of wings. Or if she uses it to give everypony else wings...or...

...Oh.

The look of sheer dread on her face was one that any passing pegasi were sure to take with them to bed that night.

Author's Note

Given what this is based on, I could have done this with Starlight, but I'm saving that for my multi-chapter crossover story and making this oneshot about her would have thrown a wrench in that.

This is what happens when I make what I think is a good joke and don't even get a cricket chirp let alone get a leaf blowing by in the breeze. It's also what happens when I run into a bit of writer's block and need to break out of it. Two birds with one stone.

(I could have also taken this concept and stuck true to what I was actually referencing -- that is, changing forms from human to unicorn -- but thinking about it more and more, it felt a little strange to have Sunset be able to switch forms without traveling between worlds. Especially since the human world has actual true-to-real-life horses.)

(...At the time of writing this, the image is glitched, but if you're familiar with EqG, you should hopefully know what I'm getting at here.)