Chapter Text
One minute, Kirishima was defending against a villain with a growing quirk and the next, he was being picked up and and slammed by his weird partner straight into Bakugo. He'd let go his unbreakable form and collided hard with the other boy, only to wake up back to the pavement, lip split and mouth full of blood. He sat up, flexing to harden himself and found that his hands just flexed in their...gloves?
He looked to see green and orange padded gloves on his hands...Bakugo's grenade gauntlets, and-
“Young Bakugo! Are you all right?”
His arms were pale, less bulked up than his own, but still impressive.
His head swam at the build of his body, the tank top, he saw that mole on his bicep, right at the edge of Bakugo's glove and blanched.
“Oh my god.” his voice was that tell-tale rough voice. It was a higher octave than his own, with a slight rumble to it that indicated it might turn gravelly. It was the final nail in the coffin.
“I'm fine, just got hit by a goddamn rock, Kirishima why didn't you-!? WHAT THE FU- WHAT!?”
Kirishima's head snapped up at the sound of his own voice and he felt his stomach lurch as he saw himself rise up unsteadily from the pavement. His scowl was fierce, full rows of sharp teeth on display as his gaze met his own?
Confusing.
“What the fuck.”
He and Bakugo were each other.
**
“Well the villain may have got away, but luckily we know who they were. The quirk will wear of in two week's time or until we catch them and break it. It wouldn't interfere too much in your regular studies.” was what Best Jeanist said, except Kirishima was devastated.
“Two weeks...”
“Yeah, don't remind me! This is your fault!” Bakugo snapped and Kirishima recoiled. Bakugo growled in his voice,” Get that look off my face! You've had worse!”
They had had to go to each other's agencies to dress out of costume and Kirishima wished he was in a better mood to tease Bakugo at how tightly he cinched his belt compared to how big his pants were, but refrained.
“Dude, can you wear my belt at least?”
Bakugo rolls his eyes and lifts his un-tucked shirt,” I am.”
“I mean the right way!”
With an irritated huff, Bakugo hikes up his pants and belts them properly and shoves Eijirou with an irritated,” Well if I gotta, then you gotta sag yours! I look lame!”
Bewildered, Kirtishima shakes his head,” These pants don't even fit you to begin with! I'm trying to keep your pants from falling down at this point bro! Is that what you want?!”
Bakugo just kicks at the pavement,” This is so stupid.”
When they return to the dorms, Aizawa is waiting for them, looking more exhausted than usual. He meets them at the gate,” So, I'm to tell you that while you're switched, in heroics classes, you must observe only. Understood? Looks like I can't erase this quirk.”
Bakugo grimaces, Kirishima's sharp teeth on full display in a terrible expression. Is that how his face really looks when he's mad? Or is Bakugo using weird face muscles he doesn't even know about!?
“Aizawa sensei,” Bakugo says, teeth clenched,” Can't you reconsider? We can practice with each other's quirks at least! I don't-”
Aizawa holds up a hand and Bakugo glares at the space between his feet as their teacher sighs,” What use would it be to get familiar with this when you'll be back to normal soon enough. Just sit tight until it blows over. That's all I wanted to say so you're dismissed.”
Kirishima bows and Bakugo gives a jerky nod before he stalks off. Kirishima catches up easily with a groan,” Heroics is my favorite class! I can't-”
Bakugo spins suddenly, a wide, ferocious grin on Kirishima's face and he shudders,” We need to at least be competent with each other's quirks if we want to participate.”
“You heard Aizawa, dude! There's no way-”
Bakugo steps into his space, and Kirishima realizes suddenly what an imposing figure he cuts. With sharp hair, red eyes and pointed teeth, with Bakugou's signature glare twisting it, it makes Eijirou's heart stop,” I am not going to fall behind because of some shitty villain. I won't. How about you? I...”
Bakugo grumbles lowly into the air between them, and Eijirou finds it weird to hear his voice attain its regular, soft cadence and low timbre,” I'm going to the gym to practice. Follow me or don't.”
Of course, Kirishima follows. He hasn't set off an explosion yet, but then again, he doesn't know what triggers it.
As expected this time in the after noon, the training bay is empty. Bakugo sets down Kirishima's backpack and shrugs off his blazer and starts unbuttoning his shirt.
“Thanks for remembering man.”
Bakuigo snorts and Kirishima thinks Bakugou's arrogance on him looks awful, sharper,” I'm just cheap. If I ripped it I'd have to buy you another one.”
Kirishima takes off Bakugou's blazer and rolls up his sleeves. He's always liked looking at Bakugou's forearms as he worked and now, he can see them up close. The pale blonde of his arm hair, the corded lines of his tendons right beneath the skin. Faint scars and imperfections.
“So I notice yours is just like flexing, but since the nerve endings sort of go numb, it's an endurance thing right?”
Kirishima realizes Bakugo has been talking to him the whole time. He's been flexing his arms and hardening them with ease.
“How do you keep your arms hard, and move at the same time?”
“Practice.” Kirishima says,” With a physical quirk like mine, you just sort of, keep an image in mind? I think of it like a second skin.”
Bakugou's eyes narrow in concentration,” How do you make your whole-”
Bakugo goes full unbreakable for just a second and grins manically,” Nice.”
Kirishima grits his teeth, trying hard not be bitter about how easily Bakugo seems to be controlling his quirk.
“Hey are you even trying to make an explosion or are you just hoping it'll go off?”
Bakugo grabs his hand and-Are his hands really that rough? Kirishima feels his own palms scrape roughly over Bakugo's smooth ones and sees himself frown,” You'll need more sweat than that. That's why my costume has gloves, but my skin naturally has a thin layer of glycerin-sweat so try-this.”
When Bakugo flexes his hand, it momentarily hardens into a clawed talon and the other boy goes,” Huh. It's the same concept as your hardening. Easy shit. Go ahead.”
Kirishima tries, but seeing Bakugo's hands, he isn't sure he remembers how exactly he hardens. Before, it was second nature, now, he's worried he won't know how much effort to put into it, how much-
“You're overthinking it, idiot.” Bakugo slaps the back of Kirishima's upheld palm and he's startled by the sudden thunder of an explosion.
Bakugo's grin spreads across his face,” See? Easy shit.”
Bakugo makes him try again and again, until Kirishima has a handle on it before he declares,” Try propelling yourself. Don't take too firm a stance or the blowback'll tear my fucking arms off and I'll have to do the same alright? Go.”
Kirishima tries for a bigger explosion, using the whole palm of Bakugo's hand and is suddenly thrown to the side, into Bakugo.
At least he knows for sure he's built himself pretty solidly because Bakugo doesn't budge,” You're supposed to use your other hand to counteract it. Try again.”
Bakugo works him hard until he's dripping sweat and his shoulders are aching from the blowback of stronger and stronger explosions. He's nowhere near as graceful as Bakugo in the air, but he can launch himself pretty high, and break his falls now.
“If there's too much sweat, just wipe it on your pants. That's easier than teaching you how to fucking limit yourself.” Bakugo says after a particularly big explosion,” You're nowhere near my level, but it's good enough. Tomorrow's Monday which means we have one more day to get a handle on this shit before Heroics on Tuesday.”
Bakugo grins wide and sinister with all of Kirishima's jagged teeth,” This shit's in the bag, Kirishima so lighten up a little.”
Rudeness aside, it's weird to hear his standard cheery voice from a third person point of view. It's weird watching himself the way Bakugo swaggers around in his body, slumped forward and snarling.
Bakugo frowns, and on Kirishima's face, it's obvious he's concerned, but he doesn't say anything,” Might as well sleep it off. I'm usually in bed by now but I don't feel tired. You a night owl or something? Fucking weird.”
Kirishima bites at his lip before speaking,” It's gonna be real weird tomorrow, Bakugo.”
It doesn't even begin to scratch the surface of Kirishima's concerns, but Bakugo shrugs it off before shrugging on Kirishima's shirt without buttoning it and declaring he's going to shower. Kirishima follows.
**
Bakugo is thrumming with excitement when he wakes up. He and Kirishima decided it would be too weird to sleep in each other's beds so they just took each other's uniforms to wear and slept in their respective rooms. Bakugo wakes and it's when he takes his bathroom caddy that he realizes something pertinent.
He needs to use Kirishima's toothbrush because no way is he going to tear his own toothbrush to shreds on Kirishima's teeth. He stomps back down the hallway and kicks open Kirishima's door and is momentarily bewildered by the sight of himself twisted into his sheets and face first in a pillow, one hand dangling from the bed.
“Kirishima!”
“BWAAAAH!”
Bakugo grimaces at the raspy yelp of his own voice and sighs,” Where the hell do you keep your toothbrush because there's no way in hell I'm using mine!”
“Dude, what-oh my god what time is-OH MY GOD I SLEPT THROUGH MY ALARM! MY HAIR MY-”
Bakugo grabs Kirishima and shakes him roughly to shut him up,” Toothbrush. Now.”
While Bakugo's waiting, he realizes that Kirishima had slept through his alarm, and he himself had woken up way before he usually did. Usually he rolled out of bed, threw on his uniform and went to class. Kirishima's routine was more involved. It started with his hair, which Bakugo hadn't bothered to do.
Kirishima looks upset suddenly as he stares at Bakugo and then pointedly at his hair,” You need to style it. It takes three minutes juts to set much more time to style it! We-”
“Are you kidding me? No.”
Kirishima scowls and finally, Bakugo feels less weirded out looking at himself. Seeing himself flail about left him feeling out of place.
Kirishima is quiet as he gets his own bathroom caddy and they switch toothbrushes. They brush their teeth side by side, and Bakugo realizes that his usual method of just killing all the plaque by scrubbing them out just rips the bristles out on Kirishima's freakish teeth. Sighing, he reaches into Kirishima's caddy to unpack a new brush and works a bit more carefully. He finishes, but ends up picking bristles out from between Kirishima's gums,” The hell's with your teeth! Fuck.”
Kirishima spits into the sink, examines his own teeth and plucks a comb from his basket.
“Ugh, you don't need that.”
Kirishima says nothing, popping open his hair gel and lining the comb with it,” It's not for me, don't worry. It's for you.”
“I told you I'm not-STOP THAT RIGHT NOW YOU SHIT!”
Kirishima drags the comb through his hair to part it and Bakugo tries to snatch the comb away, but in his body, Kirishima is faster.
“Do my hair or else I'll do the other side.”
“Fuck y-OKAY FUCK STOP THAT SHIT!”
Bakugo snatches the gel from Kirishima and slaps it into his hair-or well Kirishima's.
“Your hair's dry as shit.”
“Hey! Don't forget to-”
“I KNOW! IT'S NOT THAT FUCKING HARD!”
“Kiri, why the hell are you-OH MY GOD!”
Bakugo tenses at Kaminari's voice and snarls at Kirishima's reflection as he teases the hair in imitation of what he knows to be Kirishima's hairstyle.
“Hey Kami!” Kirishima chirps and Kaminari splutters. Bakugo groans,” Wipe that goofy smile off my fucking face idiot!”
“Actually don't!” Kaminari says grinning,” Recreate it so I can catch this on film for future generations to marvel at-”
“You're not gonna live through this generation if you so much as reach for your phone you git!” Bakugo snaps and Kaminari's mouth drops open stupidly,” Dude, that expression does not belong on Kiri's face! To be honest, I kinda didn't believe what I'd heard when Iida told us.”
“Great.” Bakugo spits and tries to focus on making those two little twin horns Kirishima makes out of his oddly cut bangs.
“Dude, that's actually...not bad.” Kirishima says reluctantly and before Bakugo can say,” Of course! Like it's that hard-”
Kaminari cuts in,” EWWWWW! Don't compliment people in Bakugo's voice.”
Instead, Kirishima smiles brightly,” Kaminari, you're a cool dude!”
He throws in a thumbs up and Bakugo screeches,” THAT'S ENOUGH!”
Kaminari looks shell shocked,” Dude, Kiri, I've never seen you mad but damn...”
“I know,” Kirishima says,” Scary.”
Bakugo pauses, unsure how to proceed now that his friends have been properly cowed? Usually, they laugh it off, but Kirishima's...
Kirishima, with his deep voice and muscular stature is intimidating.
What the actual fuck.
Bakugo washes the gel off his hands, and surveys his work,” The fact that I can do this at all is fucked up. Must be muscle memory huh.”
Kirishima's head snaps up at that and with it, the flattened part in Bakugo's hair fluffs up,” Maybe? I dunno.”
“This is so weird,” Kaminari says for what feels like the umpteenth time and Bakugo sighs.
“You're telling me.”
They leave the bathroom and Kaminari catches up with them to ask Kirishima,” Hey so what's it like being a centimeter taller than usual? Life changing? At least you aren't slouching like this guy! You actually get to be taller!”
“I never thought of it that way...To be honest, it's not much of a difference.”
Seeing Kirishima saying he hasn't given it much thought with his voice rubs Bakugo the wrong way. He should never sound uncertain, shouldn't look thoughtful.
Maybe this is how others see him?
Bakugo shudders. Is this how the whole two weeks is going to go?
Breakfast is uneventful. Kirishima insists he eat eggs over rice to take in the proper amount of protein and grouses,” You skipped my morning jog. That means during break you gotta do some kind of cardio and-do you think they'll let you use my weights during break?”
Bakugo sighs,” Can you...not do that with my face? It's fucked up.”
Kirishima looks bewildered and Katsuki supposes it's a lost cause,” Whatever. I can do a shit ton of push ups, but you gotta stop that smiling shit.”
“I...I can try.”
Bakugo scowls,” Try isn't a part of my vocabulary, Kirishima. You do it.”
“Fine, fine. As for you, would it kill you to look a little happy?”
“ What's there to be happy about this early in the morning? In this shit situation?”
Kirishima sighs,” Good point.”
Kirishima slumps in his chair, head bowed to pout at the table as he eats his own eggs over rice and grimaces,” It doesn't taste good...”
“Put hot sauce on it,” Katsuki suggests,” Or some ketchup. Whatever. I don't like plain eggs on rice. I can't imagine my taste buds changed to suit your uncultured, shitty palate.”
“You mean I have to eat like YOU!?”
Bakugo shrugs. Sure enough, after Kirishima dabs his eggs with ketchup, because he's too much of a baby for hot sauce, he wolfs it down easy enough. It's as Bakugo thought. Even though they're the same people, the fact they're in different bodies has changed some things. Their biological clocks are tuned to what their bodies are used to, and it seems there are still taste preferences.
Bakugo takes note of these things, even if now it feels like useless knowledge. Who cares if Kirishima had the palate of a little kid?
“Hey, you know what'd be funny?”
Bakugo looks up and Kirishima is grinning wide.
Is his grin always so full of teeth and almost manic?
“We should act like we got switched back suddenly.”
“What?”
“Dude, you have to admit it'd be hilarious seeing them confused and like expecting us to be switched , but we're the same!”
Bakugo hums, he sort of wants to. He knows Kirishima better than anyone else, but isn't sure he can keep a smile on his face as his default expression. He opens his phone camera and barely lifts the corners. With Kiri's wide mouth and big eyes, it looks believable.
Bakugo scowls,” I hate lying.”
Kirishima grins,” Then how about a bet?”
“I'm listening.”
“I bet we can convince Aizawa by this time tomorrow and get included in hero training.”
Bakugo grins,” He'll probably figure out it's us when we actually train, but it'll be too late.”
Kirishima grins wickedly with Bakugo's face and they bump fists.
“Alright shitty hair. No fucking around.” Kirishima says.
Bakugo allows himself a laugh,” You got it Bakubro. It'll be a cakewalk. If anything, you'll be the one to blow it. “
Kirishima shakes his head, scowl fierce, and Bakugo would think he was looking in a mirror if not for their situation,” If you think that, get ready to be a stepping stone on my way to the number one spot.”
Bakugo consciously grins, lifts a hand up to hold his shoulder as he rolls it, typical Kirishima shit,” Oh you're on!”