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Derek should have known that standing next to Stiles, or even being in his general vicinity at any given time was an atrocious idea. Especially when they were confronting witches. He’d only intended to be close enough to pull Stiles out of the way if his plan of talking the witch down ended poorly, which it clearly had, and instead he got this result. The witch had looked between the two of them, raised one of her neatly manicured brows, and the rest had been blackness. Twenty minutes later, he’d regained consciousness approximately five feet to the left of where he had fallen and sprung up with the intent to hunt the witch down. It took one attempt to figure out that springing was not on the menu as his body toppled forward, gangly and horrendously off-balance. He’d barely broken his fall with a pair of oddly familiar hands that radiated pain when a groan sounded behind him and he turned to see his own body crumpled on the concrete.
It just didn’t get weirder than this. Now Derek sat in a chair in the McCall household kitchen, watching his body inspect itself. Or rather, Stiles using his hands to look over his arms, which were now technically Stiles’, because somehow the witch had swapped their bodies.
Like he’d thought, it had been a terrible idea.
"Stiles, what the hell are you doing?" It looked as though he was examining Derek’s biceps, for heaven’s sake. What could possibly be so fascinating about a bicep?
"Shhhh." If watching his body do things he wasn’t telling it to do was bizarre, hearing his voice say things he wasn’t saying was ten times stranger. Hell, even thinking about that sentence hurt his head. But Stiles was still using his fingers to trail over the hairs that covered the back of his forearm, then contorting the limb around to stare intently at the inside of his wrist. He looked absolutely enthralled, and Derek wanted to bat his hands away in embarrassment.
"Would you just—!" Without really thinking about it, he found his hands waving through the air in true Stiles fashion. It was almost like a reflex, except for the fact that Stiles’ reflexes absolutely sucked. Derek was beginning to wonder how he managed to walk half the time.
"Shhhhh!" And now he was being hushed by himself. Irritated, he rounded on Scott in the hopes that he could control his friend.
”Scott, tell him to stop touching my body.” There was a sentence he hadn’t ever wanted to say.
Scott just looked between them and shrugged, a smirk curling the corner of his lips. “What? It’s your body. You tell him.” He seemed infinitely amused at Stiles’ inspection, as though he knew something was going to happen because it had happened before. Oh god.
"Scotty, will you do me a solid and dig up the notebook and a ruler? Oh, and grab the measuring tape out of the kitchen drawer." Without further prompting, Scott popped out of his chair and trotted out of the room, returning moments later with a beaten green notebook, a pencil, a ruler, and a white measuring tape. Derek could only watch in horrified awe as the items were arranged next to his body before Scott moved off to the side, crossing his arms behind him like some B-movie laboratory assistant.
Stiles examined the tips of his fingers, the palms, and then flicked out his claws easily.
"Stiles, stop! You could hurt someone with those; they are not toys!” His own face regarded him with an expression of cool disdain before clawless fingers were waved in his direction.
"Relax, dude. Your body has way better control than you give it credit for." Derek looked helplessly at Scott, who only raised his brows and kept looking amused. Then they both stared silently as Stiles measured each of his claws, then the distance between his heel of his palm and the longest middle claw. With a hum, he flicked open the green notebook and took the pencil in hand to write down the measurements.
Derek wasn’t sure if it was Scott or Stiles who was more surprised when the letters came out sloppy and weak. It certainly produced identical frowns as Stiles switched the pencil from his right hand to his left before continuing his notations.
"Dude, you never told us you were left-handed." It was Derek’s turn to fix them with a look before sniffing contemptuously and shrugging.
"You never asked."
He wanted to be irate about all of this, yet strangely found that he…wasn’t. For some reason, he perfectly understood why it was so imperative that Stiles have all this information written down, the residual curiosity echoing through his own mind. All of his senses were currently dulled and yet he still felt oversensitized and overstimulated, as though he would burst apart at the seams if he didn’t start moving. Stiles was always jiggling his leg or tapping his fingers to the point that he produced a constant stream of background noise, but Derek had never understood why until today.
Stiles was a living, breathing ball of energy and curiosity.
Trying to sit still was like trying to cope with his bones being settled incorrectly beneath his skin, each one pushing at the fine membrane of it until Derek thought he was going to rattle apart from within. His mind raced unintentionally, flipping through thoughts like the channels on a television. Was this Stiles’ brain at all times? No wonder he always seemed to know the answers to the most arbitrary questions; he noticed everything and his mind whirled so fast that Derek’s thoughts could hardly keep up. He was starting to forgive the more random outbursts now.
"Fang to tooth length ratio is bigger than yours, buddy." His mind zoned back in just in time to see Stiles remove a ruler from his mouth and scribble something else down. Scott frowned, looking at the sheet, then looked heavily put out by whatever was on it.
"Maybe it’s because he’s born." Stiles only snorted, which looked doubly odd in Derek’s body.
"You know what they say about guys with big fangs…" Scott promptly cuffed him around the ears and Stiles actually stuck his tongue out, which was both a stunning display of maturity and possibly the oddest thing anyone had seen all day. Scott paused for a moment, eyes wide in shock, before he doubled over laughing and Stiles grinned in response.
"Oh my god, I need to get a video of that for posterity. Derek’s face just stuck his tongue out, holy shit. I didn’t even know that was possible for him." Stiles’ brain supplied Derek with approximately fifteen other things he could do with Derek’s body, and there was an odd chemical reaction to at least four of them.
"Both of you, knock it off." Stiles and Scott took one look at the glare plastered on the real Stiles’ face, and broke down again in uncontrollable hysterics.
"Sure thing, dude. I promise I’ll start researching a way to break this…as soon as I get a pic of you throwing up a few gang signs." At least his body was getting a kick out of all of this.
Derek could only pinch the bridge of Stiles’ nose and sigh. It was going to be a long night.