Twilight blinked a few times at the sound and looked up from her books, craning her neck just in time to see the mechanical bird retreat into the clock mounted above her bed — the bed that she should have by all rights been in by this hour. "One AM... the Princess will be raising the sun in a few hours, but... I'm still not that tired," The studious unicorn thought out loud as she turned back to her books; there was no way a quiet voice could awaken Spike at this time of night, and she had let Owloysius out an hour ago to find some food.
Thinking of her number-two assistant's dinner made Twilight a touch squeamish; she knew it was all part of the natural order of things, but creatures eating other creatures still felt wrong to her, no matter what logic dictated. She still cursed her curiosity for the day that she had asked Fluttershy how she fed her more carnivorous patients. The answer she had gotten from the timid pegasus had given her terrible nightmares for a week.
Shaking her head as though it would clear the nastiness out of her mind, Twilight threw herself back into her evening's studies: cross-referencing historical mentions of advanced transformative spells with their modern counterparts. She began to hum to herself as she got back into her groove, a passage in the modern spellbook prompting her to flip carefully through the older, mustier tome with her magic in search of a reference she had seen earlier.
So engrossed was Twilight in her studies that she failed to notice when her aimless little tune picked up a second part, harmonising seamlessly with her own. It was only when Twilight paused for a moment and the humming continued that the oblivious mare realized a suddenly terrifying truth: she was not alone. She turned to her right, where her vision was abruptly filled with energetic blue eyes and poofy pink mane, and she did what any sensible pony would do in such a situation:
Jump into the air and scream like a little filly.
"Shh! You'll wake up Spike!" the pink intruder whispered loud enough to wake the sleeping dragon herself, and Twilight managed to calm herself enough to notice that her unexpected visitor wasn't a terrible book thief, but simply Pinkie Pie. Taking a few deep, relaxing breaths, Twilight took a quick survey of her surroundings; she quickly confirmed that both doors and windows were as sealed against the library-disorganizing power of the spring winds as they had been when she had let Owloysius out earlier.
"Pinkie, how did you get in here?" Twilight asked, managing to hide most of the irritation in her voice. It wasn't like she minded a visit from Pinkie — indeed, a part of her that she had been trying very hard to ignore for the past few months was ecstatic about seeing the pink party pony — but she could have done without the near heart attack.
"Well, I was trying to get a good night's sleep, 'cause the Cakes need me to open Sugarcube Corner all by my onesies tomorrow, but—"
Twilight interrupted with her best librarian's shush; by some Luna-granted miracle, Spike hadn't been woken up by either the unicorn's scream nor Pinkie's extreme whispers, and Twilight wanted to keep it that way.
"—oh, right, sorry! So where was I, oh, right, well, I was trying to sleep, but my ears kept a-twitching back and forth, like a metronome or a pendulum or those funny clacking-ball things that important big shot ponies put on their desks so they can play with toys even when they say, 'Oh, no, I'm too big and important to play with toys!' I mean, who are they trying to fool!? Anyway, the twitchy ears with the perfect rhythm, that means that somepony is up way too late! So I hopped out of bed and looked out my window, and sure enough, the only light on in all of Ponyville was at the library, so I came over here!"
Twilight brought a hoof to her face as Pinkie's explanation came to an abrupt and unsatisfying end. "Pinkie, that was 'why', not 'how'! And I'm not up too late." She shot a hoof towards her clock. "It's barely past one AM! I stayed up way later than this all the time when I lived in Canterlot."
"Well, no wonder you never had any friends before you came to Ponyville!" Pinkie exclaimed, nodding to herself as though some great truth had been revealed. "I mean, Luna wasn't around back then, so your only possible friends would have been terrible vampire ponies, and let's face it, with a name like Twilight Sparkle, you probably shouldn't hang out with vampires." As Twilight blinked at the strange leap Pinkie's logic had just taken, the energetic earth pony turned her attention to the books Twilight had been studying moments earlier. "So what ancient and forbidden knowledge is worth losing a comfy night's sleep over, huh?" she asked, no sarcasm detectable in her voice despite the words.
Twilight flustered for a second as Pinkie's sudden movement shoved her tail right in the unicorn's face, but the thought of losing her place in the books quickly got her brain working again. "Pinkie, be careful! I don't want to have to find my spot in those books again, and the one is very old and fragile." She breathed a sigh of relief as her words had the desired effect, Pinkie's snout only a hoof away from touching the older tome before it stopped. "Thank you, Pinkie. Now, I'm not sure if you'll understand this, but—"
"Hey!" Pinkie's tone was indignant as she looked back up at Twilight, faint tears visible in her blue eyes. "I may not be the smartest smartypants in the world like you, Twilight, but I'm not dumb! I—"
"No, I didn't mean it like that!" Twilight interrupted in a panic, mentally cursing herself for causing Pinkie Pie to almost cry. Placing a reassuring hoof on Pinkie's shoulder, Twilight gave her friend her most sincere smile. "Pinkie, you're very smart, and very perceptive. There's plenty you could teach me, alright?" Rubbing the tears out of her eyes, Pinkie nodded, a smile slowly returning to her lips. "All I really meant was that unicorn magic is very difficult to explain to a non-unicorn; it involves concepts that wouldn't even make sense to you. It would be, like... It would be like if you described a cake recipe to a pony who didn't know what baking was."
"What!?" Pinkie shouted, a horrified expression on her face. "There's a pony who doesn't know what baking is? Quick, Twilight, point me to this poor pieless pony, so that I..." A glare from Twilight made Pinkie trail off. "Oh, right, that was a metaphor, wasn't it?"
"A simile, actually, but yes."
Pinkie gestured to the older tome. "Well, if you want to be able to explain your spooky complicated unicorn magic to me, perhaps you should cast that spell." Blinking at Pinkie's sudden suggestion, Twilight walked back over to her books and began to read the ancient spell enshrined in the old tome's pages.
"Hmm... 'Exclaim's Exigency Exchange'..." Twilight mumbled out loud as she read through the spell's description and instructions. "'Requires focus on two ponies, the casting pony can be one'... Seems to last for sixteen hours from the time of casting, so a solid day... 'Best cast at night, as transformative magic is the domain of the moon,' really? Tell me something a filly in magic kindergarten hasn't already learned... 'Offers a new perspective to both ponies?' Ha!"
Shaking her head at what she had just read, Twilight looked up at Pinkie with a wry smirk, her friend's expression betraying her curiosity. "These old spells have this annoying habit of being deliberately cryptic about what they actually do, but 'offer a new perspective,' when the spell requires two ponies? This spell would switch us in some sort of way, Pinkie; either our minds would be in each other's bodies, or you'd become an unicorn while I'd become an earth pony." She closed her eyes and chuckled. "Not exactly the type of spell one casts on a whim, now is it?"
Twilight could only open her eyes and stare at Pinkie Pie in disbelief, a flat "what" barely getting past her lips.
"Well, it's like you said, the spell tries to be all secretive but it's so obvious what it actually does, duh!" Pinkie replied, her excitement over what the spell meant making it impossible for her to stand still. "But wouldn't that be fun? I'd love to spend a day in the horseshoes of the genius unicorn Twilight Sparkle, favourite pony of the Princess! Mastering magic, snarking with Spike, offering helpful hints to overcome any hindrance."
“I don’t know, Pinkie...” Twilight trailed off, the lack of conviction in her voice evident. Pinkie’s enthusiasm was terribly contagious.
Pinkie smiled, the knowing smirk of one who knows she is about to win, and delivered her coup de grâce: “And I bet you’ll learn a thing or two about me as well...”
Logically, Twilight still knew that this was a bad idea, but between sleep deprivation, Pinkie’s silver tongue, and those traitorous thoughts in the back of her mind, she finally relented. “Alright, I’ll cast the spell.” Pinkie began to cheer, but was stopped before she could let a peep out by a purple hoof. “But! You have to promise me that you will be very careful with my magic. I know it might seem to you that I can do almost anything, and I will admit that I'm pretty powerful, but I have my limits, and more importantly, so do other ponies. So no lifting anything bigger than yourself, no using magic directly on yourself or others, and above all, think everything over twice."
The solemn look Pinkie gave Twilight as the unicorn finished laying down the rules filled her with hope that this wouldn't end in disaster after all. "I will follow all of your rules. Cross my heart and hope to fly, stick a cupcake in my eye." Twilight nodded and turned to prepare the spell, but was unexpectedly stopped by Pinkie's hoof on her shoulder. "And in exchange... My rules: have fun! Help others have fun! And do not, under any circumstances, think everything over twice!"
Twilight chuckled as she repeated the motions of the Pinkie Pie Swear, somehow managing to not poke her own eye this time. "Cross my heart and hope to fly, stick a cupcake in my eye. Okay, the spell calls for us to be about five hooves apart - no more, no less - and it suggests that we lay down in case we lose consciousness," Taking her spot five hooves from Pinkie, Twilight tucked her legs under her and laid down before floating over the ancient spellbook to consult with.
As soon as Pinkie had made herself comfortable, Twilight started forming the spell in her horn, paying close attention to make certain she got it right. The horn's glow doubled and then doubled again as Twilight layered the spell's component matrices together, requiring more and more of her magical reserves to hold the spell together and prevent it from dissipating. "Okay, Pinkie..." she gasped out after a minute of concentration. "Brace yourself!"
In an instant, Twilight released the power she had been building up, and for a moment, she could feel everything about Pinkie Pie: the laughter, the songcraft, the insecurities that she held deep under the surface, every feeling and thought and fleeting desire the pink party pony held. And she knew that Pinkie would be feeling everything about her, and she suddenly felt a twinge of panic, knowing that those feelings she had been bearing for months would be laid open to Pinkie, a possibility she had never considered.
But before the panic could overtake Twilight, a torrent of unfathomable power hit her, and she lost grip of her consciousness, sinking down into bizarre dreams.