Chapter Text
“How. In the hell. Is it always you two?” Aizawa pinched the bridge of his nose in both exasperation and desperation.
Katsuki continued holding still to his crimson glare, blatantly ignoring the twitching movement of cat ear’s on his head.
Cat ears. And a tail, too, by the way. But fucking cat ears.
Because Katsuki, who was minding his own business on a patrol with his work study, was hit with a fucking transformation quirk.
He’d already gone through the usual “Are you fucking kidding me’s” to “This is fucking bullshit’s” finally making it to this point of begrudgingly and reluctantly accepting the events that had transpired.
As the details of the quirk were explained, it only made him angrier.
First, the fucking cat ears, twitching and springing up in response to literally everything.
Second, a long, fluffy tail swishing and swooshing without his brain’s permission.
And then, finally, learning that soon enough he would be a cat. No, not the weird, shitty, hellish cat boy bullshit he was currently dealing with- but an entire cat.
Fur and fucking everything.
For at least the next three days.
With his eye twitching, he stood by his teacher steadfast as they learned the rest of the details of the quirk.
Aizawa sighed when the random citizen who had definitely just fucked Katsuki’s life sideways finished her explanation. “Thank you, we’ll be in touch should we need anything.”
The citizen bowed her head apologetically, and Katsuki fought against himself to stay quiet.
The two of them were walking back to the dorms now, Katsuki absolutely fuming while Aizawa kept a watchful eye on him through his peripheral, smirking.
Crimson eyes snapped in his direction, blonde cat ears flattening in rage. “Not. A fucking. Word.”
Aizawa chuckled- fucking chuckled- but didn’t straighten out his expression. “You may be able to hide the ears for a bit, but that tail is definitely going to give you away.”
Katsuki reached behind him, grabbing the tail in a fiery grip and holding it at his side. It couldn’t give him away if he just ripped the damn thing off, right?
“Can’t you do something about this shit? I’m gonna miss classes and fall behind if I can’t hold a fucking pencil.” Katsuki attempted to bargain, to which Aizawa shrugged.
“It’s a transformation quirk, Bakugou. I can hold it off for a moment, but as soon as I blink it’ll come back full force.” He explained. “It has to run it’s course. Think of it like the flu.”
“Yeah, but if I had the fucking flu, I’d still have my hands!” The blonde barked back.
Or maybe meowed.
He thrust his hands up in anger as he spoke, stomach dropping as soon as he realized his hands were already gone, having turned to paws. Aizawa stifled a laugh, and Katsuki furiously shoved his paws down into his pockets.
After a long, grueling walk, they finally arrived at the dorms.
Katsuki stood in front of the door, unmoving. Aizawa raised an eyebrow in question before the realization dawned on him. He smirked again. “Need me to get that for you?”
Katsuki was about to explode.
Aizawa shook his head, grabbing the doorknob but hesitating before actually opening it.
“Look, I know I was being a jerk, but I am sympathetic to your situation. If you want, I’ll go in there and debrief your classmates or make them leave so that you can get to your room without confrontation.”
The blonde considered that for a moment, but ultimately decided against it. He wasn’t a fucking coward.
“No. I’ll tell them my damn self, and I’ll tell them to leave me the absolute fuck alone until this shit’s over.”
“I hope you know I’m only excusing the cursing because of your situation.” His teacher shrugged again, pulling the door open and motioning for Katsuki to take the lead.
To his dismay, basically everyone in their class was in the common room when he got there, entranced in a vicious round of Mario Kart.
He pushed himself against the wall, fixing his tail to be stuck behind his back as he did so. There wasn’t shit he could do about the ears, however.
Aizawa eyed him, making Katsuki curse again under his breath. It’s now or never, he supposed. Maybe he should still tell them about it and make it a point to tell them to also fuck off about it before he lost the ability to do so.
Or maybe his furious meows could be translated by Koda, but that would be fucking embarrassing.
He straightened himself a bit before raising his voice to catch their attention.
“Idiots.” He called, but none of them responded, apparently all deciding that watching the blue shell on it’s mission to fuck over Sero’s Luigi was way more important.
“Hey.” He tried again, a little louder. Still, watching Todoroki’s King Boo slam Ashido’s Shy Guy off Rainbow Road.
Aizawa rolled his eyes. He knew Katsuki wasn’t giving this his all, but honestly he couldn’t exactly blame him. This would be humiliating for anyone.
His scarf reached across the room in a swift motion, grabbing the television and effectively yanking it from the stand and to the ground, causing the screen to smash.
The entire class went silent immediately, their heads all collectively snapping to Aizawa and Katsuki’s direction.
The blonde immediately tensed, breaking his wide eyed stare from the obliterated tv to the faces of his fellow future heroes, who were all currently looking at him with equally wide stares.
“…The fuck?” Denki was the first to break the silence.
Katsuki’s ears flattened as his breathing picked up, faster and faster. Now was NOT the time for a fucking panic attack, he was already dealing with enough humiliation.
But now, he was forced with explaining why he only had mere hours to continue being human. That was a bitch in of itself.
Deku’s big ass green eyes were also practically glued to him, which on a good day made his heart do stupid somersaults and flips in the dumbest way possible, but today wasn’t a good day. So today, it made him want to shrink in on himself until he evaporated to nothing.
Why the fuck couldn’t he be hit with a turtle transformation quirk? At least then he could fucking hide in the fucking shell.
It just had to be a cat, didn’t it?
He blinked himself back to his fucky reality. “Alright, fuckwads. Listen up cause I’m only gonna say this once.” He tried to feel as confident as he sounded, but this really sucked.
“I’m sorry, did you steal my win in Rainbow Road so you could make some stupid announcement?” Sero called from his spot on the couch, joycon still clutched firmly in his hand.
Momo facepalmed beside him. “That’s the fifth television I’ve had to purchase this month.”
Uraraka gaped at her. “You’ve been buying them?! Why didn’t you just make one?!”
She gasped, completely taken aback. “And throw off the economy?!”
“Guys.“ Izuku called from his place by Uraraka, shooting them an abnormally annoyed look. “Can you let Kacchan finish?”
Katsuki wondered if it was possible to either scoff or glare away the butterflies in his stomach. Eh, worth a shot. “Shut the fuck up, Deku.”
Izuku turned back to him with a frown. Before he could respond, Katsuki interjected again.
“I got hit with a fucking transformation quirk.”
If he didn’t have their attention before, he certainly did then.
“And, uh, I’m…” His fists clenched in his pockets, or they would have, if he still had hands.
Come on, Great Explosion Murder God DynaMight. Spit it the fuck out, already.
“He’s going to be a cat for the next three days.” Aizawa finished for him, to which Katsuki fumed at.
“You wanna tell them while you still have the ability to do so, or not?” Aizawa shot him a disapproving look.
Predictably, the entire class was up in shouts and questions about it.
All except for Deku, who looked downright worried as fuck, his eyebrows arching as he met the blonde’s crimson gaze.
And Katsuki didn’t want his fucking pity. He averted his eyes as if the look burned him.
“Yup, so now you assholes know what’s up. I’m going to my room, so leave me the fuck alone and I’ll see you in three days or whatever.”
“Three days?! What about-“ Kirishima tried after his best friend, but cut himself off once Katsuki began to stalk away, tail swooshing lowly behind him.
That was certainly a sight.
Aizawa took a step forward, causing Izuku to pause on his way to follow the blonde.
“There’s one more thing,” their teacher began once Katsuki had left the room.
“I know he doesn’t want it, but I need one of you to keep an eye on him. Don’t be overwhelming, but if he’s hungry get him food, if he’s thirsty get him water. And DON’T,” he was looking directly at Izuku now. “Do anything to upset him in that state.”
The greenette’s shoulders slumped. It wasn’t like he tried to piss Kacchan off, it just sort of happened sometimes.
They were on better terms now, being in their third year at UA. The war had helped mend their relationship, too. Izuku could finally call Katsuki his best friend again.
Which meant he was allowed to worry now, and if Kacchan bitched about it, Izuku could just bitch back.
That’s what happens after you save the world, you end up growing a backbone.
…He may have still been trying to convince himself he had one. But fake it till you make it, right?
“Yes, sir.” The greenette surrendered.
Aizawa nodded. “Good. Then, any volunteers?”
Before Izuku could so much as form a syllable, the Bakusquad all raised their hands, immediately disqualifying him.
Izuku pretended that it didn’t make him incredibly jealous at the thought that his best friend, who he absolutely had feelings for, wouldn’t be cared for in this state by himself.
And yeah, whether Kacchan was human or not, Izuku wanted to be the one caring for him, and holding his hand… and watching movies pressed up against each other on the couch while resting his head on his shoulder-
Whatever. He was jealous, but that didn’t mean he could allow himself to admit to it or act upon it. He’d just repaired his friendship with the blonde. It was delicate, but precious. He just wanted to protect it, even if he couldn’t cross that distance with him.
“Alright. Keep me updated on his condition, and let me know if anything goes wrong.” Aizawa shifted his gaze. “And Iida,” The class rep locked onto him. “Keep an eye on them while they keep an eye on Bakugou.”
“Yes, sir!” Iida responded, saluting their teacher who rolled his eyes in response.
—————
It was a couple of hours later when it happened.
Katsuki was simply laying in his bed, starring up at the ceiling in complete and utter boredom.
He didn’t have hands, so he couldn’t use his phone or study.
His tail was swooshing uncontrollably. Back and forth, back and forth. And try as he may, he just couldn’t make it stop.
He turned over on his side, but suddenly fell directly towards the floor with a thud as soon as he landed.
He groaned, eyes widening in dread once he realized…
Everything suddenly looked so much bigger.
The space under his bed looked wide enough to fit an entire truck under.
His rolling chair looked to be miles away.
His dresser was tall enough to require rock climbing gear.
He attempted to push himself up, looking down at his forearms in shock.
He knew it was going to happen. He was dreading it but fucking dammit, it was here now.
His arms were covered in soft blonde fur. His clothes surrounded him in a heap of fabric on the floor.
He tried to stand on two feet but immediately fell over again onto his hands.
…paws-
He was a full cat now. And he was pissed.
And as if things couldn’t get shittier, a knock suddenly rang out from his door.
His head snapped up at the sound, ears curling back in embarrassment and anxiety.
Fuck.
“Hey, it’s me. Can I come in?” Kirishima called from the other side cheerfully.
Katsuki’s eyes darted around the room. What could he do? He couldn’t exactly tell him to fuck off, and knowing Kirishima- he was about to just walk in, anyway.
It was a normal thing for the two of them at this point. Knocking was just a curtesy for Katsuki’s current condition.
Katsuki attempted a curse under his breath out of habit, wanting to absolutely shrink in on himself when all that came out was a low meow.
FUCK YOU, TRANSFORMATION QUIRK
“Alright, dude. I’m worried now, so I’m gonna come in.”
SHIT, Katsuki panicked, diving under his bed and hiding there.
He felt pathetic.
The door creaked open slowly.
“…Bro?”
Kirishima stopped short, seeing Katsuki’s pile of clothes just inches away from his bed. He looked over to the blonde’s bathroom door, finding it to be open- the light not even on inside.
Katsuki stayed vigilant from his place under the bed, watching Kirishima’s shoes as he walked around the room.
This was so fucking lame of him. But he told them to leave him alone until the quirk wore off. It wasn’t his fault that Shitty Hair couldn’t follow basic instructions!
He heard the redhead hum in thought before he stopped just short of his bed.
Katsuki realized in utter horror that his tail was sticking out, giving him away completely.
He heard Kirishima gasp, and he dug his claws into the ground to crawl further under the bed.
“Is… is that…” Kirishima stuttered, watching Katsuki disappear further under the bed.
What was he supposed to do? What if he was hurt? What if he needed help and couldn’t get out?
What if he had a cat brain now?
…Was he just a normal cat for the moment…?
He couldn’t take it anymore, as he gently reached under the bed and found Katsuki’s soft form.
“Heyyyy, Bakubro…” he tried to call out in a tone that he hoped wasn’t threatening. “It’s me, come on out.”
Katsuki hissed. There was no fucking way anyone could see him in this state.
He wasn’t weak, or vulnerable, or helpless. He was Katsuki fucking Bakugou.
He attempted to paw at Kirishima’s hands, inwardly willing his best friend to just go the fuck away.
But then, the strangest fucking thing happened-
“Pspspspsp!”
Katsuki’s head snapped up, turning around and rushing out to the redhead, who’s eyes flashed a mixture of concern and adoration once he finally caught sight of the blonde.
He stopped in his tracks, mortified.
He got into a threatening stance- or at least one that could be seen as threatening for a cat- and hissed again.
Kirishima shook his head affectionately. “So it happened already, huh?” Then reached over and pet him.
FUCKING. PET HIM.
Eijirou couldn’t help it, the cat version of his best friend was downright adorable. Fuzzy and soft, complete with delicate little toe beans and a fluffy tail.
Before he knew it, he was swept up in the redhead’s arms, then gently placed back down on his bed.
“Well, I came to ask if you were hungry but I’m not sure if I’ll get a straight answer.” Eijirou rubbed at the back of his neck nervously. “Or maybe I can? Can you talk?”
Katsuki meowed at him viciously. It wasn’t the least bit threatening.
You asshole! Get the fuck out of here and stop humiliating me!
Pity flashed through his eyes for a split second. “Okay, that answers that. Can you…” he tilted his head in concentration. “Can you still understand me?”
Katsuki narrowed his eyes.
“Okay, fine. If you can still understand me and you’re still, y’know- you, wag your tail or something.”
Katsuki was getting angrier by the second, but complied, hoping the knowledge that he was still himself would fucking count for something and keep the extras off his fucking back until this shit was over.
Eijirou beamed. “Cool, man! I’m glad you’re still there. I would’ve missed you.” He reached out to pet his head, but Katsuki backed away, glowering.
“Right. You’d hate that if you were human, anyway.”
I’m still human, asshat!
The redhead thought for a moment. “What can I feed you, though? Im sure you don’t wanna eat cat food… oh! Maybe I can have Sato make you some salmon? Cats eat fish, right?”
Katsuki hissed again.
I’m not a damn cat!
“Are you hissing because you don’t want salmon or are you hissing because I called you a cat? Because you know, right now, you are an actual cat.”
Katsuki lunged forward with his claws out- straight for Kirishima’s chest.
Eijirou activated his quirk upon impact, catching the blonde once he started to fall. “Relax man, I’m just trying to help! You can’t go without food for three days, so you’re gonna have to eat, and I don’t think you can make yourself food this way. Just let me help!”
Katsuki did not fucking need his help. Just because he didn’t have fucking thumbs anymore didn’t mean he needed to be cared for.
He could figure it out- cats fend for themselves in the wild all the time.
He wriggled from his best friend’s grasp, falling to the floor and landing on his feet.
He kinda forgot cats could do that- it was helpful.
Eijirou knelt down beside him. “You know I’m not trying to patronize you or anything, man. I’d never do that, I just wanna help. Like friends do.”
And dammit. That shitty look in Eijirou’s eyes kinda made him feel uncomfortable. Why could he never just accept that they were best friends without being so obvious about it all the damn time?
It made him feel guilty. Like the way his memories of fucking bullying Izuku did.
Though… he felt guilty about those memories for an entirely different reason now- one that he was still trying to completely figure out in his mind.
He wasn’t oblivious, okay? He called the fucker’s name out with his dying breath, that was pretty much the nail in his coffin- no pun intended.
And oh shit.
Three days. Three days WITHOUT Izuku.
After the war, they got into the habit of spending as much time together as they possibly could. Not an unhealthy amount, lest they get tired of each other. Even though Katsuki was CERTAIN he’d never get tired of Izuku. It was more so that he feared Izuku would get tired of him.
Again, the whole “I have feelings for Izuku Midoriya” thing was an adjustment.
But still, feelings aside, he fucking worried about him.
Along with the idiot going all vigilante and curb stomping the shit out of All For One- the entire world now knew of One For All, and villains were beginning to pop up in pursuit of it.
He couldn’t fucking protect him as a damn cat, now could he?
That may have pissed him off more than the transformation quirk did.
He felt a hand stroking his back, and heard Kirishima making calming sounds from above. He hadn’t even noticed how his tail tucked between his legs in anxiety.
It… was oddly soothing. But still fucking embarrassing.
He scrambled away from his touch with a high pitched meow.
Eijirou stood up with a sigh. “Sorry, you just looked like you needed some comfort.”
Katsuki gave him an exhausted stare, because no the fuck he didn’t.
…Maybe a little, but it was from the wrong person.
Not that he could admit that, though.
After a few more one sided-feeling-arguments, Kirishima finally began cooking Katsuki’s salmon.
The thing was, however, that Eijirou was obligated to watch over him. Probably not this closely, but Kirishima prided himself on being a good friend. So, here Katsuki was. Sitting on the counter, watching as Kirishima cooked under the notion that had anyone walked in, he would hide him immediately so that he was out of sight and therefore, away from humiliation.
And yeah, Kirishima could have left him in his room, that would have been fine.
But what if he needed something? He didn’t have thumbs, he couldn’t open his door for anything!
So, Katsuki was sitting on the counter, tail swooshing absentmindedly as he watched the redhead cook.
Plus, from here, Katsuki could claw at him if he fucked up his salmon. It was the world’s worst version of a win-win situation.
And it was going fine, until the idiot brigade got home.
Katsuki’s head snapped in the direction of the door opening, jumping up and getting ready to hurl himself in the opposite direction when Kirishima caught him mid air, hardening his hands against Katsuki’s clawing, again.
“Will you relax? It’s just the guys!”
THAT’S THE FUCKING PROBLEM.
Then, another voice caused his ears to twitch.
“Oh, yeah, you can leave if you want. Looks like they have Midoriya with them, too.”
DEKU!
There was absolutely no conceivable way he could allow Izuku to see him like this. He jumped from Kirishima’s arms and down to the ground as he gained speed towards the door.
And then, remembered he didn’t have thumbs, as he began furiously scratching at it.
Kirishima realized the issue too late.
“What the hell?!”
“Is that…?”
“Oh my gosh!”
Katsuki could feel the metaphorical goosebumps as he turned around and saw the looks on their faces.
Sero and Kaminari were doubled over in a laughing fit, as Izuku looked stuck between laughter, admiration, and sheer worry.
It was a double edged sword, mostly because Katsuki relished in the admiration Izuku gave him, even if he pretended it annoyed him, but his heart squeezed at the look of worry in his eyes. He didn’t have much time to think it over before a pair of electric hands were scooping him up.
“Awww! I knew it would happen, but I didn’t think it would be this soon!” He nuzzled the back of Katsuki’s neck before spinning around and holding him up high in a Lion King pose. “Guys, look at Cat-cchan!”
He must have had a fucking death wish, because not only was Katsuki thrashing wildly, but he was hissing with a vengeance.
Fucking Pikachu wouldn’t dare try this shit if he were human, and as soon as he could, he’d blast the dumbass to hell.
“Hey, be careful!” Izuku called, rushing over as he tried to retrieve Katsuki from Kaminari.
“Dude, he’s fine! See?” Kaminari assured, gently passing Katsuki to Izuku.
Izuku, in turn, instinctually cradled him in his arms.
Like he was fucking precious, and that did the shittiest, stupidest shit to his heart.
And without noticing his own actions, he found himself nuzzling into Izuku’s elbow and purring against his touch.
And it wasn’t his fucking fault, okay? He’d already realized he loved the shit out of Deku, and being touchy-feely with people was something he regularly avoided.
But now Deku was holding him and petting him and it felt so nice and good and warm and comforting that he couldn’t help it, dammit!
He was just purring. That’s all.
-WAIT. He was fucking purring!
Everyone had seen it, everyone had heard it!
IZUKU HAD HEARD IT.
It had been fucking loud.
Could he pretend it didn’t happen? He wanted to get as far away as possible, maybe move to a different country and change his name while he was at it.
He was pawing at Izuku’s arms, not wanting to claw at him but also wanting to fight against his instincts that caused the fucking purring in the first place!
He couldn’t let that shit happen again!
…But Izuku felt so warm and even from here, Katsuki could smell the scent of his shampoo.
He stopped once he realized what was going on, and found all their eyes laser focused in on him. Shit.
And he couldn’t threaten them or explode them either…
What the hell was he supposed to do?!
He actually may have to do that whole moving to a different country and changing his name thing.
…Unless-
Katsuki hated lying. If there was something he valued in relationships or just in general- it was honesty.
He’d never even lied to Deku when they couldn’t stand each other.
But he was getting the short end of the stick ever since he’d gotten hit with the quirk, so he decided to throw himself a bone.
He blinked up at them, tilting his head slightly, and meowing innocently.
He just needed to save himself the humiliation- that’s all- okay?!
And with these new instincts, he wasn’t even sure what he could expect from himself, if purring like a lovesick idiot at Izuku’s touch was anything to go by.
It wasn’t the best plan of action, but it was better than nothing.
Kirishima raised an eyebrow at him, but was overshadowed by the sudden coos coming from Ashido, Tsu and Uraraka as they raced over to them. Funny, he hadn’t even noticed them come in.
“Awww! Is that Katsuki? He’s soooo cute!” Mina cried as she raced to Izuku’s side, petting lightly at Katsuki’s head.
His ears flattened as he nestled himself back against Izuku’s chest.
Kirishima’s brow furrowed. Why was Katsuki acting like this…?
Like an actual cat…?
Then, he heard it, as Katsuki purred more once Izuku began petting him.
He opened his mouth to question but stopped once Katsuki sent him a quick death glare.
He looked at him and then back up at Izuku.
Oh.
Wow.
Eijirou shook his head, mouthing a quick and quiet “you suck” at the blonde, who had the biggest- cat version of a shit eating grin on his face.
Because Katsuki’s not-so-secret crush on Izuku was one he regularly bitched about to Kirishima, (best friend privileges) and now here the explosive fucker was being held and petted and overall doted on by the greenette.
So yeah, Katsuki sucked. And he was going to owe Kirishima at least three best friend hugs once this shit was over.