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Katsuki had been through a lot of weird shit in his life. Villains with body-morphing quirks, gravity-defying battles, and once— only once —being temporarily turned into a rubber duck (don’t ask, Kirishima never lets him live it down).
But this? This was some next-level bullshit.
The city streets were chaotic. Civilians scattered in every direction, their screams blending with the wailing of emergency sirens as explosions rocked the pavement. Smoke curled into the sky, the thick stench of burning rubber and scorched concrete filling the air.
Katsuki clicked his tongue in irritation. “Tch. Just had to cause a damn scene, huh?”
Across from him, a group of villains—six in total—stood with cocky grins and malicious intent. They weren’t just small-time criminals, either. These guys had quirks built for destruction, and boy, were they ugly.
“Dynamight,” one of them sneered. A burly man with obsidian skin cracked his knuckles. “Didn’t think you’d show up so fast.”
"You really think you stand a chance? That’s cute. Let’s get this over with." Katsuki’s palms popped with small bursts of heat, his grin feral as he rolled his shoulders.
Beside him, Mina bounced on her heels, hands glowing with acid. “Alright, how we doin’ this Blasty?”
Todoroki, ever the picture of calm, adjusted his gloves. “Quick and efficient,” he said simply, his breath visible from the cold mist curling around his side.
The villains didn’t wait.
The first one lunged, a beastly figure with claws like steel, but Katsuki was faster. He ducked under the swipe and blasted himself upward, twisting mid-air and delivering a brutal kick to the side of the villain’s head. The guy crumpled before he even hit the ground.
Mina spun and sent a splash of acid toward another, forcing him to dodge, but it gave Katsuki enough of an opening to land and propel himself forward with a well-timed explosion. He slammed his fist into his gut, sending them flying into a parked car.
Behind them, Todoroki lifted a wall of ice, stopping a fire-wielding villain from torching them from behind. He sent a jet of flames right after, forcing the guy to stumble back with a yelp.
Katsuki barely had time to smirk before the next attack came. A villain with a whip-like appendage lashed out, catching his ankle and yanking him off balance.
“Fu—”
He twisted mid-fall, using his quirk to blast himself free before flipping onto his feet. He turned in time to see Mina take down another enemy, her grin sharp. “Three down, three to go!” she cheered.
One of the remaining villains, a lanky figure with glowing yellow eyes, suddenly darted forward, moving unnaturally fast. Katsuki moved to intercept, but a puff of strange pink smoke exploded in his face.
His vision blurred. His head spun.
“Oh, shit—”
He staggered back as his body locked up, a tingling sensation rushing through his veins. He caught sight of the villain smirking—right before Todoroki slammed an ice pillar into them, sending them flying into a streetlight with a sickening crack. The villain slumped, unconscious.
Mina whistled . “Damn, Todoroki, remind me never to piss you off!”
Todoroki didn’t respond. His brows furrowed as he turned to Katsuki. “Bakugo. You okay?”
Katsuki scowled, shaking his head to clear it. “Yeah, yeah, I—” He froze.
Something felt weird.
Really weird.
Katsuki clenched his fists, expecting the familiar crackle of heat in his palms. Instead… his fingers twitched. But no sparks. No explosions.
“What the—?”
Todoroki’s expression darkened. “That villain’s quirk—”
But Katsuki cut Todoroki off.
“That
bastard
, I swear I'm going to kill him when he wakes up.” Katsuki seethed.
Mina let out a nervous laugh, nudging Katsuki’s shoulder. “Uh, maybe don’t threaten the unconscious guy, Bakugo. Kinda defeats the whole ‘we’re the good guys’ thing.”
Todoroki, crouched beside the villain who had cursed Katsuki with the cat quirk, examined their injuries with a detached expression. “He won’t be waking up anytime soon. You hit him pretty hard.”
Katsuki scoffed, crossing his arms. “Damn right I did. He’s lucky I didn’t blow his damn head off.”
Mina sighed, placing her hands on her hips. “Okay, yeah, we won, but… uh—” She hesitated, looking at Katsuki with wide eyes before breaking into a grin. “Dude, your tail is twitching.”
Katsuki blinked. “My what?”
Todoroki tilted his head. “You have ears too.”
“What the hell are you talking about?” Katsuki growled, but as soon as he turned his head, he caught sight of the fluffy blonde tail flicking behind him. A sinking feeling settled in his gut.
Mina clapped a hand over her mouth, shoulders shaking as she held back laughter. “Oh my god—”
Katsuki immediately reached up, and sure enough, his fingers brushed against soft, fur-covered ears on top of his head. His stomach dropped. “No. No, no, no—”
Todoroki, ever unbothered, simply stated, “It seems the quirk worked.”
Mina burst into full-blown cackling. “You’re a cat, Bakugo!”
Katsuki's eye twitched dangerously. “ You have got to be fucking kidding me .”
Before he could finish, a familiar voice called out from behind them.
“Kacchan?”
Katsuki froze. His blood ran cold. Slowly, he turned to see Izuku standing there, wide-eyed, his expression torn between concern and something that suspiciously looked like awe.
Mina, still giggling, wiped a tear from her eye. “Oh my god, this is the best day ever.”
Todoroki hummed. “This should be interesting.”
Izuku stepped closer, blinking rapidly, his face turning red. “Kacchan… you have cat ears.” after a moment of hesitation “A-and a tail.”
Katsuki groaned, running his hands over his face.
“I swear to god, if anyone breathes a word of this—”
But before he could finish his threat, Izuku let out the softest, most flustered giggle Katsuki had ever heard.
Katsuki’s tail swished and his ears twitched.
A low growl escaped his mouth before he could stop it.
Izuku’s hands flew to his mouth, his shoulders shaking as he tried to hold back his laughter.
“K-Kacchan, did you just—”
“Shut the hell up, nerd.” Katsuki’s voice was a mix of embarrassment and frustration, but the effect was completely ruined by the way his tail flicked aggressively behind him.
Mina clutched her stomach, wheezing. “Oh my god—Bakugo, you growled ! Like—like an actual cat!”
Todoroki tilted his head. “It was more of a low rumble, actually. Like a warning.”
Izuku took another cautious step forward, his eyes locked onto Katsuki’s ears. “Kacchan… do you feel different?” His voice was oddly gentle, his curiosity overriding any sense of self-preservation.
Katsuki scowled, baring his teeth. “What the hell kind of question is that?” But just as he moved to glare at Izuku, his ears flattened against his head, betraying his irritation.
Izuku’s gaze softened. “I-It’s just… I think your ears move when you’re upset.”
Mina gasped dramatically. “Wait, do they move when you’re happy too?!”
Todoroki reached out, as if testing a theory. “I wonder if—”
“ Touch me and die, ” Katsuki snapped, his tail puffing up slightly.
Todoroki withdrew his hand. “Fair enough.”
Izuku, however, was still staring, eyes wide and practically sparkling with fascination. Katsuki tried not to let it get to him, but then Izuku murmured under his breath—almost like he didn’t realize he was speaking—
“...You’re kinda cute like this.”
Silence.
Mina inhaled sharply. “Oh my god.”
Todoroki blinked. “Huh.”
Katsuki’s entire body locked up. His brain short-circuited. His tail bristled. And worst of all— his ears twitched forward.
Izuku gasped softly, his cheeks flaring red. “They moved!”
Katsuki grabbed the nearest piece of rubble and launched it at Mina before turning on his heel and storming off. “I’m going home, and none of you idiots are coming with me!”
“But Kacchan—”
“NO!”
Mina, now lying on the ground from dodging Katsuki’s attack, rolled onto her back and cackled. “Ohhh, this really the best day of my life.”
Todoroki simply nodded. “We should tell Kirishima.”
“DO NOT TELL KIRISHIMA!” Katsuki roared from a distance.
Izuku was still standing there, watching Katsuki stomp away, his heart hammering.
He was so doomed.
------------------
“Bakugo, we're putting you under house arrest.”
Katsuki’s tail spiked.
“All Might, you can't be serious,” Katsuki snarled, his ears pinning flat against his head. His tail lashed behind him like an agitated whip.
All Might, simply crossed his arms and gave him a firm look. “Young Bakugo, this is for your own good.”
“The hell it is!” Katsuki snapped, throwing his hands up—only for his tail to flick aggressively behind him again. “I didn’t ask to get hit with some damn cat quirk, and I sure as hell don’t need a damn babysitter!”
All Might sighed, rubbing his temples. “This isn’t up for debate. Until we’re sure that quirk’s effects aren’t permanent, you’re under house arrest.”
Katsuki’s eye twitched. “I swear to god —”
“And Young Midoriya will be in charge of keeping an eye on you.”
Katsuki froze. His whole body went rigid as his ears perked straight up, and his tail puffed out like a bottle brush.
“ WHAT?! ”
As if on cue, there was a hurried knock at the door before it swung open to reveal Izuku, panting slightly as if he had sprinted there. “I—I got your call, All Might—what’s going on?”
“Midoriya, perfect timing!” All Might beamed. “I need you to stay with Young Bakugo until we’re sure the quirk will wear off naturally.”
Izuku blinked. “Wait… stay with him?”
All Might nodded. “Yes. Observe his behavior, ensure he doesn’t get into any fights, and most importantly—” he looked pointedly at Katsuki, whose tail was now lashing so violently it looked like it might detach from his body— “make sure he doesn’t leave the house.”
Katsuki let out a strangled noise of pure rage. “ Like hell he will —”
But before he could finish, Izuku, still flustered and clearly processing what was happening, suddenly blurted out: “Wait, does this mean I get to pet him?”
Silence.
Katsuki’s pupils shrank. His ears flattened again. His tail bristled again.
Izuku, realizing what he had just said, turned scarlet . “I—I didn’t mean—I just—your ears—they’re—”
Katsuki growled low in his throat, his tail flicking furiously. “ I am going to kill you. ”
All Might sighed, adjusting his grip as Katsuki flailed uselessly in the air. “Well, this is already going great . ”
“I’m a Pro-Hero for god's sake, and if Deku’s watching me, who the fuck will look after the agency?”
“I’m sure we can manage.”
Izuku swallowed hard, still red in the face, while Katsuki wriggled in All Might’s grip like an enraged cat about to be dunked in water. His ears twitched aggressively, tail snapping back and forth as if it had a mind of its own.
“I swear —if you don’t let me go right now, I’m going to—”
“Young Bakugo,” All Might interrupted, voice firm but not unkind. “The decision has been made. We can’t risk you going out in public with your instincts compromised.”
Katsuki scoffed. “Compromised? Compromised? I’m still the No. 2 hero, and I could blast my way through a villain attack right now! ”
Izuku’s gaze flickered to Katsuki’s tail, which, despite its violent thrashing, puffed up slightly at the praise.
All Might, ignoring him, sighed. “Your agency will be fine. You’ve trained them well. Consider this an unexpected vacation.”
Katsuki stilled. “A vacation? ”
“Yes.”
His expression darkened like a storm cloud. “I hate vacations.”
Izuku had to bite back a laugh at how absurdly stubborn Katsuki was. “Kacchan, it’s not that bad.”
“Oh, yeah?” Katsuki snapped, whirling on him. “ You’re not the one stuck in your apartment with a babysitter while your tail’s got a damn mind of its own! ”
Izuku opened his mouth to argue but then watched in real-time as Katsuki’s tail flicked toward him—before curling around his wrist in an unintentional, instinct-driven movement.
Silence.
Izuku and Katsuki stared at it.
All Might hummed. “Well, that’s new.”
Katsuki immediately yanked his tail back like it had been burned. “WHAT THE FUCK?!”
Izuku, still frozen, turned even redder if that was possible. “U-uh, Kacchan—”
“ No one speak. ” Katsuki jabbed a finger at both of them, face redder than his own explosions. “I will fix this and then—then we will never speak of it again!”
All Might chuckled. “I’d suggest getting used to it. You’re stuck together for the time being.”
Katsuki scowled, his ears twitching as he crossed his arms. “This is the worst day of my life. ”
Izuku, rubbing his wrist absentmindedly where Katsuki’s tail had just been, definitely wasn’t going to be getting over this anytime soon.
------------------
As soon as Katsuki stepped into his apartment, he shoved the door shut with his foot and yanked his hood off. His ears twitched freely, no longer pressed awkwardly under the fabric, and he let out a long, deep sigh of relief.
“Finally.” He muttered, tossing the hoodie onto the nearest chair before flopping down onto the couch. His tail flicked lazily over the armrest as he sprawled out, muscles relaxing now that they were out of public view.
Izuku, still reeling from the chaos of the day, blinked before shaking his head. “I’ll, um—make some tea.” He shuffled toward the kitchen, eager for something normal to do.
Katsuki merely grunted in response, stretching one arm over his eyes, exhaustion creeping up on him after everything that had happened.
A few minutes later, Izuku returned with two steaming mugs of green tea. He hesitated for a moment, watching the way Katsuki’s tail curled over the couch’s edge, before clearing his throat.
“Here, Kacchan.” He held out the mug.
Katsuki cracked one eye open, then sat up, grabbing the cup with a small huff. “Thanks.” He took a careful sip.
And then—
Purr.
Izuku froze.
Katsuki froze.
The deep, vibrating purr rumbled from Katsuki’s chest, his tail swishing lazily in satisfaction. His ears twitched in time with the sound, and for a split second, he looked completely at peace.
Izuku, on the other hand, was short-circuiting. His face burned , his hands tightening around his own mug as his brain struggled to process what just happened.
Did Katsuki just—
Did Kacchan just—
Purr?
Katsuki took another sip, utterly unaware of what he’d just done, and—there it was again. A soft, involuntary purr of approval.
Izuku almost dropped his tea.
Katsuki finally noticed the intense stare he was getting and scowled. “What?”
Izuku’s mouth opened, closed, then opened again. “Y-you—”
Katsuki raised a brow. “What? Spit it out, nerd.”
Izuku gulped. “You just purred. ”
Silence.
Katsuki blinked. “…What?”
Izuku set his mug down carefully, as if afraid his shaking hands might betray him. “You—You just purred, Kacchan.”
Katsuki stared at him like he’d just been personally insulted. “The hell I did . ”
“You did! ” Izuku insisted, voice rising slightly.
“No, I didn’t! ”
Izuku grabbed his phone. “I’m recording next time.”
“Like hell you are!”
But the moment Katsuki took another sip—
Purr.
Izuku squeaked.
“Okay what the fuck is up with you Deku?”
Izuku was vibrating at this point, his face redder a tomato. “I—I can’t help it! Kacchan, you’re purring! ”
Katsuki scowled, ears flicking in irritation. “The hell kinda reaction is that?! It’s just—” He stopped mid-sentence, his eyes widening slightly as realization dawned.
It was real.
The steady, involuntary rumbling was coming from his own chest. The moment he took another sip of tea, it started again, deep and traitorously content.
Katsuki slammed the mug down on the coffee table like it had personally betrayed him.
“ Oh, hell no. ”
Izuku practically lunged forward. “No—keep drinking! I need to test something!”
“The fuck you do!” Katsuki shot back, ears flattening as he shoved the mug away like it was poison. His tail fluffed up slightly in distress, making Izuku let out another embarrassingly high-pitched sound.
Katsuki pointed at him accusingly. “If you laugh, I’m throwing you out. ”
Izuku frantically waved his hands. “I-I’m not laughing! I just—” He took a deep breath, though his voice was still very wobbly. “It’s just—you were purring because you liked the tea, Kacchan.”
Katsuki narrowed his eyes. “That’s stupid.”
“It makes sense!” Izuku argued. “Your body’s probably responding to pleasant stimuli because of the quirk’s side effects. The tea was warm, you were relaxed—it triggered a reaction!”
Katsuki crossed his arms, glaring at the offending mug like it had personally wronged him. “…So you’re saying I have no control over it?”
Izuku nodded. “Pretty much.”
Katsuki twitched. His tail flicked violently. “ Bullshit. ”
Izuku looked like he was fighting for his life to stay calm. “I-I can try to help you suppress it if you want?”
Katsuki exhaled sharply through his nose. “Yeah, well, you better, because if anyone hears about this—”
Buzz!
Both their heads snapped toward Izuku’s phone.
A message notification. From Ochaco.
Ochako: Did Bakugo get hit with a cat quirk???
Silence.
Katsuki turned his head back, slowly, dangerously, toward Izuku.
Izuku, still gripping his phone, paled instantly. “I—”
“ YOU FUCKING NERD! ”
Izuku’s heart pounded as he bolted down the hallway, Katsuki’s enraged voice hot on his heels.
“GET BACK HERE, YOU FUCKING NERD!”
“It was for science!” Izuku yelped, narrowly dodging a flying couch pillow as he skidded around the corner.
He had no idea where he was going—he was running on pure adrenaline, feet carrying him deeper into Katsuki’s apartment. His pulse roared in his ears, breath coming in sharp pants.
Behind him, Katsuki was gaining.
Izuku turned another corner and—
Shit.
He ran straight into a dead-end. Katsuki’s bedroom.
He barely had time to register his mistake before the door slammed shut behind him.
Trapped.
Izuku spun, but Katsuki was already lunging. He dove for the bed in a last-ditch effort, scrambling toward the middle, twisting the sheets and pillows into a mess in his panic. His breath was heavy, eyes wide as he tried to scuttle away.
Too late.
Katsuki tackled him down with zero hesitation, his hands planting firmly on either side of Izuku’s head as they landed in a heap of tangled sheets.
The world tilted. Izuku felt himself sink slightly into the plush mattress beneath them.
Katsuki hovered above him, his weight pinning Izuku down just enough to remind him that escape was impossible.
Izuku swallowed hard, face burning as he stared up into crimson eyes that gleamed with pure, unfiltered triumph.
“Gotcha.” Katsuki’s voice was low, rough, and smug as hell.
Izuku’s mind was short-circuiting.
His hands twitched at his sides. He had no idea what possessed him—maybe it was exhaustion, maybe it was stupidity—but before he could stop himself, his fingers moved on their own.
Slowly, hesitantly, he raised one hand.
And touched Katsuki’s ears.
Soft.
So soft.
Katsuki froze .
Izuku wasn’t breathing.
He knew he should pull away—he knew this was basically a death wish—but the moment his fingers brushed through the fur, a deep, involuntary rumble vibrated against his palm.
Izuku’s stomach flipped .
Katsuki purred.
And instead of pulling away, his head leaned into the touch.
Katsuki’s body slumped slightly forwards, his eyes becoming half lidded, and out of instinct Izuku’s hand flew from his head to rest against Katsuki’s chest.
That was when Katsuki broke from whatever trance he was in.
He stiffened. His ears twitched, and his tail gave a sharp flick, the haze in his eyes vanishing in an instant.
Izuku barely had a second to react before Katsuki jerked back like he’d been burned.
“What the fuck was that?!” Katsuki barked, his voice cracking just slightly. His pupils were blown, face an alarming shade of red.
Izuku, still lying flat on the bed, blinked up at him, equally flustered. “I—I don’t know! You purred again , and—”
“I did not ,” Katsuki snarled, but there was a dangerous amount of uncertainty laced in his voice.
Izuku sat up on his elbows, his brain scrambling for an explanation that wouldn't get him killed. “Y-you kind of did, Kacchan… and you—uh—you leaned into it.”
Katsuki twitched. “No, I didn’t. ”
“Yes, you did. ”
Izuku watched as Katsuki’s eye twitched.
" Shut up! ” he barked, yanking the hood of his sweater over his head like it would somehow make this entire conversation disappear. His tail lashed violently behind him, ears pressed flat against his skull.
Izuku swallowed down his laughter, knowing full well it would be the last sound he ever made if it slipped out. Instead, he cleared his throat, shifting to sit up properly.
“Okay, okay, I won’t mention it again,” he promised. Then, after a pause, he added, “But you really did purr.”
Katsuki let out a noise that was somewhere between a growl and a strangled screech.
Izuku, feeling stupid again, scooted close to Katsuki again, and lifted his hand to pet him again. When he looked up, his hand hovering near Katsuki’s ear, Katsuki was looking at him like a kitten.
Katsuki's eyes were wide, his pupils blown slightly, ears twitching but not moving away. His tail had stopped its furious lashing, now swishing lazily behind him. He looked… hesitant. Curious.
Izuku swallowed. His heart was hammering, and he had no idea why he was doing this—but the way Katsuki was looking at him, like he was both ready to murder him and melt into his touch, had him completely entranced.
Slowly, gently, Izuku closed the last bit of distance and let his fingers graze over one of Katsuki’s ears.
Soft.
Katsuki shivered.
Izuku sucked in a sharp breath, his fingertips now tracing along the base of Katsuki’s ear. “K-Kacchan…?”
Katsuki blinked at him, his expression clouded, his breathing suddenly uneven. His ears twitched under Izuku’s touch, but he didn’t pull away. Instead, his body swayed—just slightly—leaning into Izuku’s hand.
Izuku’s heart nearly stopped.
Then—
Purr.
Katsuki’s eyes widened in horror. Izuku’s jaw dropped.
The sound—low, deep, content —rumbled through Katsuki’s chest, vibrating against Izuku’s palm.
A beat of silence passed between them.
Then—
“I—” Katsuki’s voice cracked. He launched himself backward, nearly falling off the bed. “ FUCK! ”
Izuku blinked, still processing what just happened.
Katsuki was already yanking his hood further over his head, ears hidden, tail bristling aggressively. “You saw nothing. You heard nothing.”
Izuku, still sitting in the middle of the bed, mouth slightly agape, finally let out the breath he was holding.
“…Kacchan.”
“I swear to god, Deku—”
“You just purred again! . ”
Katsuki grabbed a pillow and chucked it at his face.
“Shut up, Shut up, Shut up.” Katsuki groaned, his face flaring red.
Izuku barely managed to catch the pillow before it smacked him in the face, but his brain was too fried to do anything else. Katsuki purred. Again. Not just once—multiple times.
And the worst part? Izuku liked it.
“Wait—” Izuku sat up, gripping the pillow. “Why do you purr so much?”
Katsuki visibly stiffened . His ears flattened immediately, tail spiking up like a warning sign. “What kind of fucking question is that?”
Izuku, however, had already fallen deep into his muttering spiral.
“Do you like purring? Does it happen when you’re comfortable? Does that mean you like me—wait, no, that’s not what I meant, I mean, you obviously tolerate me but—”
Katsuki groaned, dragging a hand down his face.
“—Or maybe it’s subconscious? Maybe your body reacts to certain stimuli—like warmth or comfort, but why does it happen when I touch you? That can’t be a coincidence, right? Unless—”
Izuku yelped as Katsuki suddenly lunged, tackling him again.
“Deku, shut the fuck up before you give yourself an aneurysm.” Katsuki huffed, gripping Izuku’s wrist before hauling them both off the bed.
Izuku, flailing slightly, barely had time to register where they were going before he found himself dragged into the kitchen.
“W-what are we—?”
“Dinner.” Katsuki deadpanned, shoving a pan onto the stove. “Unless you wanna starve. ”
Izuku blinked, momentarily thrown off by the sudden shift, but as Katsuki turned his back to him, something caught his eye.
Katsuki’s tail—before bristling in irritation—was now lazily flicking back and forth. Not in frustration. Not in warning.
It was relaxed.
Izuku’s gaze trailed upward. Katsuki’s ears—normally pinned back or twitching aggressively—were at ease, standing naturally as he moved around the kitchen.
The realization hit Izuku hard.
He was comfortable .
Katsuki never looked this relaxed.
Izuku’s face exploded into red.
Katsuki, noticing the silence, glanced back at him. “Oi. Why the fuck is your face so red? Do you have a fever?”
Katsuki raised one hand and gently placed the back of it against Izuku’s forehead.
Izuku’s brain short-circuited.
Katsuki’s hand was warm —rough and calloused, but gentle as it rested against his forehead. His ears twitched slightly, his tail giving a slow, lazy flick.
Izuku thought he might actually die.
“I—I’m fine!” he blurted, stepping back so fast he nearly tripped over his own feet. “Definitely no fever! Nope! All good!”
Katsuki narrowed his eyes. “You sure? You’re acting like a weirdo .”
“I am a weirdo,” Izuku said weakly, gripping the counter like it might somehow save him. His heart was going way too fast, and the worst part? Katsuki was still watching him, ears perked slightly in curiosity.
“Whatever,” Katsuki finally muttered, rolling his eyes as he turned back to the stove. “Just don’t pass out in my kitchen.”
Izuku swallowed. He needed to stop thinking about this. He needed to focus.
He forced himself to step closer, watching as Katsuki started chopping vegetables with sharp, precise movements. Izuku was not going to stare at his tail. He was not going to stare at his ears. He was not going to—
His gaze flickered back to them anyway.
They were still relaxed. Completely relaxed.
Izuku bit his lip, eyes darting away as he felt his face heat up again.
He was doomed.
------------------
A week later and Katsuki’s condition was no better.
“Fucking hell, its been a whole damn week.” Katsuki sighed, his tail licking back and forwards in irritation.
Katsuki scowled at his reflection in the window, watching as his ears twitched and his tail lashed behind him like an agitated cat about to pounce. A whole damn week, and the stupid quirk hadn’t worn off. He was sick of it. Sick of the twitching, the involuntary tail movements, the way his body seemed to react on its own to—
“Ahhh, that was refreshing,” a voice sighed from the hallway.
Katsuki turned, and his heart skipped a beat.
Izuku stood there, fresh from the shower, towel slung around his neck, his hair still damp and messy from being towel-dried. A few stray droplets trailed down his collarbone before disappearing under the loose shirt he’d thrown on.
Katsuki’s ears perked straight up. His tail froze. Then—without his permission—it gave one slow, lazy flick.
Izuku blinked at him. “Uh. Kacchan?”
Katsuki immediately forced a scowl, willing his ears to flatten. “What?” he snapped, pretending he hadn’t just had a very concerning reaction.
Izuku, oblivious as ever, just sighed and rubbed his stomach. “I’m starving.” He turned and headed for the kitchen, mumbling, “Let’s see what we have…”
Katsuki took a deep breath, shaking himself out of whatever that had been, and trailed after him.
Izuku pulled open the fridge and let out a groan. “Kacchan,” he called, slumping against the counter. “We need to go grocery shopping.”
Katsuki rolled his eyes. “No shit.”
Izuku turned to him with a deadpan look. “So let’s go?”
Katsuki crossed his arms, tail flicking again in irritation. “Tch. Fine. But if anyone dares say a word about my tail, I’m blowing up the whole store.”
Izuku chuckled, grabbing his wallet. “I’ll keep you from committing crimes, don’t worry.”
Katsuki muttered a curse under his breath and grabbed his jacket, ears flicking with barely contained irritation.
This is gonna be a long fucking day
------------------
“We need apples.”
“No, we don’t.”
“Oh! Can we get this?”
“No.”
Izuku huffed, holding a pack of mochi in his hands. “But Kacchan—”
“We have sweets at home,” Katsuki grumbled, scanning the shelves for the essentials. His tail flicked lazily behind him, and his ears twitched every time Izuku made a dramatic whining noise.
They had been bickering like this for the past fifteen minutes, their basket filling up with mostly reasonable groceries. Izuku, however, kept slipping in things they definitely didn’t need.
Katsuki was just about to snatch the mochi out of Izuku’s hands when a small giggle interrupted them.
“Kitty!”
Both of them turned to see a little girl, maybe four years old, standing a few feet away, beaming up at Katsuki with sparkling eyes. His tail flicked again, and she giggled even more, bouncing on her heels.
“Kitty!” she said again, making grabby hands toward him.
Katsuki stared at her, frozen. What the fuck.
Izuku, on the other hand, melted instantly. “Aw, hey there,” he greeted, crouching down.
The girl blinked at him before suddenly making grabby hands at him instead.
Izuku laughed, glancing at Katsuki, who was still glaring at the kid like she’d personally offended him. “I think she wants me to pick her up,” Izuku whispered, amusement clear in his tone.
“Don’t you dare, ” Katsuki warned.
Izuku ignored him completely, scooping the little girl into his arms with ease.
She wiggled happily, then reached out again—toward Katsuki.
Katsuki took a small, instinctive step back. “No.”
The girl pouted.
Izuku raised an eyebrow at him. “Kacchan, come on, just let her—”
“I said no.”
The girl pouted even more, and Izuku sighed dramatically. “You’re so mean, Kacchan.”
Before Katsuki could bark out a response, the girl reached forward—and gently patted his ears.
Katsuki stiffened, but he didn’t jerk away.
Izuku blinked.
The little girl, giggling softly, continued to stroke his ears with tiny, delicate fingers. Katsuki's tail, traitorous as ever, swayed in slow, relaxed movements. His ears twitched slightly under her touch, but he let her do it, staying perfectly still.
Izuku watched, mesmerized. Holy shit.
Katsuki Bakugo—explosive, terrifying, perpetually grumpy Katsuki—was standing there, letting a tiny child pet his ears like some kind of domesticated cat. And he wasn’t blowing anything up.
Izuku swallowed, suddenly feeling weirdly warm as he stared at Katsuki’s completely relaxed expression. He was so—so gentle with her.
After a moment, the girl let out a happy sigh and patted Izuku’s chest. “Down!”
Izuku carefully placed her back on the ground, and just as he did, a frazzled-looking woman rushed over.
“Oh my goodness,” she sighed in relief. “I’m so sorry—she ran off the moment I looked away!” She scooped the girl up, pressing a quick kiss to her forehead.
“She wasn’t any trouble,” Izuku assured, still sneaking glances at Katsuki.
The woman smiled gratefully. “Thank you so much. Say bye-bye, sweetie.”
The little girl wiggled in her mother’s arms, still grinning at Katsuki. “Bye-bye, Kitty!”
Katsuki’s eye twitched, but before he could say anything, the mother nodded her thanks and walked off.
As soon as they were out of sight, Izuku turned to Katsuki, smug.
“You liked that.”
Katsuki scowled. “Shut the hell up.”
“You did! You let her pet you, Kacchan.”
“Drop it, nerd.”
Izuku snickered. “Kacchan, do you actually like getting petted?”
Katsuki immediately shoved the shopping basket into Izuku’s arms and stomped toward the checkout. “I’m leaving your ass here.”
Izuku, still grinning like an idiot, jogged after him. “Kacchaaaaan, answer the question!”
“Go fuck yourself.”
------------------
Izuku took a sip from his mug and flipped the page midway through. Carefully, he set the mug down and buried his nose back into the book, fully engrossed in the words on the page.
That was until a familiar grumble interrupted him.
Katsuki stomped into the room, arms crossed, tail flicking behind him in an impatient rhythm. His ears twitched, but Izuku didn’t look up. He was so close to finishing this chapter—
Another grumble. This time louder.
Still, Izuku didn’t react.
Katsuki’s eye twitched. His tail flicked more aggressively.
And then— smack.
Izuku barely had time to register what was happening before Katsuki slammed his book shut, his hands bracing against the table as he loomed over him. His ears were twitching erratically now, tail flicking behind him in sharp, irritated snaps.
“What the hell, Kacchan?!” Izuku yelped, quickly pulling the book back toward him. He frowned, looking up, and that was when he noticed.
Katsuki wasn’t just grumpy. He was waiting.
Waiting for him.
Izuku swallowed.
No. No way. That couldn’t be it.
…Could it?
Hesitantly, he lifted the book again, watching Katsuki carefully as he cracked it open.
The moment his eyes flicked back to the pages, Katsuki huffed, ears flattening slightly, and—
Smack.
The book was closed again.
Izuku turned red.
Oh my god.
He wants attention.
Katsuki was standing there, ears twitching, tail flicking, demanding attention like a cat.
Izuku opened his mouth, closed it, then opened it again. He had no idea what to do with this information.
His brain short-circuited.
Katsuki, growing impatient, scowled. “What?”
Izuku stared at him, still stuck between disbelief and something very dangerous that he refused to acknowledge.
Finally, voice slightly squeaky, he muttered, “Kacchan… do you want me to pet you?”
Katsuki went rigid. His tail froze mid-flick. His ears twitched once—twice—then immediately flattened.
And then he exploded.
“WHAT THE HELL, DEKU?!”
Izuku flailed, barely dodging the pillow Katsuki hurled at him.
“YOU WERE THE ONE ASKING FOR ATTENTION!” Izuku shouted, face still burning.
“THE FUCK I WAS—”
Izuku huffed, exasperated. “You literally just—ugh, never mind!”
He ran a hand through his hair, cheeks still pink, before hesitantly reaching forward. “Just—hold still, okay?”
Katsuki’s eyes narrowed suspiciously.
Izuku took a deep breath—then lightly scratched behind one of his ears.
Katsuki jerked at the contact—then, to Izuku’s absolute horror —he purred.
Loudly.
Izuku felt his entire soul leave his body.
“…Oh my god.”
But instead of pulling back, Katsuki nuzzled his head forwards and into Izuku’s hand even more.
Izuku forgot how to breathe.
Katsuki, Katsuki, had just nuzzled into his touch.
Like a damn cat.
Izuku’s brain short-circuited so violently that all he could do was sit there, hand frozen against the soft blonde hair, while Katsuki practically melted into his palm. His ears twitched slightly, tail flicking in lazy, contented motions.
Izuku swallowed.
This was dangerous.
This was so dangerous.
But before his sanity could fully reboot, Katsuki sighed —a deep, low rumble from his chest, and—
Oh no.
He was purring again.
Izuku was officially doomed.
His fingers twitched, and against all better judgment, he began rubbing behind Katsuki’s ears more firmly, experimentally scratching at the base.
Katsuki shuddered.
Izuku swore he almost blacked out.
This wasn’t happening. This couldn’t be happening.
Katsuki— loud and explosive, Katsuki —was leaning into his touch, eyes slipping half-lidded, completely relaxed, completely content.
Izuku, meanwhile, was spiraling.
What was he supposed to do with this?!
His best friend—his childhood crush that he’d spent years trying to shove into the back of his mind—was literally purring in his hands, acting like the world’s most temperamental but affectionate cat.
And Izuku was weak.
His fingers kept moving, almost instinctively now, scratching at the base of Katsuki’s ears, smoothing over his hair, dragging lightly down to his jaw—
Katsuki let out a low, pleased hum, and Izuku nearly combusted.
I’m dead. I’m so dead.
And then— oh no.
Katsuki’s tail flicked—and wrapped around Izuku’s wrist.
Izuku squeaked .
That was enough to snap Katsuki out of it.
His entire body went rigid. His ears twitched and then flattened completely as his eyes snapped open.
For a long, painful second, neither of them moved.
Then—
“OH FUCK—”
Katsuki launched himself backwards, nearly toppling over the couch.
Izuku scrambled up, just as flustered, heart racing as he gawked at Katsuki, who was now standing a full five feet away, looking like he wanted to combust himself.
They stared at each other, wide-eyed,Katsuki’s ears and Izuku’s face was completely red.
“…W-we don’t talk about this,” Katsuki finally muttered, voice strained.
Izuku, still feeling like he’d been struck by lightning, nodded rapidly. “R-right. Never happened.”
A long, tense silence stretched between them.
Katsuki’s ears twitched again.
Izuku, despite everything, noticed.
And then, even worse—
He thought about how soft they were.
His face somehow got redder.
Groaning, Izuku buried his face in his hands and sighed.
Why, why, why, why —
Why was this happening to him?
Why was Katsuki like this?
Why was he still thinking about the way Katsuki melted into his touch, the way his tail had wrapped around his wrist, the way his ears twitched so adorably—
Izuku smacked himself in the face.
No. No. He refused to go down this path.
Katsuki was Katsuki. His childhood friend, his best friend. The same Katsuki who used to yell at him for breathing too loudly. The same Katsuki who cussed people out for looking at him wrong. The same Katsuki who—
—was still standing there, ears flicking, arms crossed, tail swishing with obvious irritation.
Izuku swallowed hard.
“…You good?” Katsuki finally grumbled, though his voice still sounded suspiciously strained .
Izuku peeked between his fingers and nodded furiously. “Mhm! Yep! Totally fine!”
Katsuki squinted at him. “You don’t look fine.”
“Well, I am!” Izuku all but shrieked, his entire body stiff as he forced himself to sit normally. “I’m great! I’m perfect! I’m—”
He choked on air when Katsuki’s tail flicked again.
Katsuki scowled, running a hand through his hair like he also wanted to punt himself into the sun. “Tch. Whatever. I’m making food.”
Without another word, he stomped off toward the kitchen.
Izuku let out a breath he hadn’t realized he was holding, slumping forward until his forehead hit the coffee table.
He was not okay.
Not even a little bit.
But then—
A loud crash from the kitchen made him jolt upright.
“FUCKING—”
Another clatter.
“Kacchan?” Izuku scrambled to his feet, rushing toward the source of the chaos.
He turned the corner into the kitchen and found Katsuki, standing in the middle of what could only be described as an apocalyptic mess.
A cutting board had been knocked to the floor. A pan was barely hanging onto the edge of the counter. The fridge door was open, a carton of eggs halfway to tipping over, and somehow— somehow —there was flour in Katsuki’s hair.
Izuku blinked.
Katsuki twitched.
“Say one word and I’ll kill you,” he growled.
Izuku immediately pressed his lips together, desperate not to laugh.
But then he saw it—
Katsuki’s tail was poofed out.
Like a goddamn angry cat.
Izuku wheezed.
And that was it.
Katsuki launched a handful of flour at him.
Chaos ensued.
Izuku coughed and sputtered and when he looked up he found Katsuki looking very smug.
Izuku lunged towards him.
Katsuki barely had a second to react before Izuku tackled him.
They crashed against the counter, rattling the pan that was already precariously close to falling. Izuku wrapped his arms around Katsuki’s middle, trying to wrestle him to the ground, but Katsuki was strong— too strong.
“You little shit— ” Katsuki snarled, his tail flicking wildly as he fought back.
Izuku gritted his teeth, locking his arms tighter around Katsuki’s torso, determined to win —
—until Katsuki twitched.
And purred.
Izuku froze.
Katsuki stiffened.
Neither of them moved.
The rumble of Katsuki’s purr filled the silence.
Izuku, still clinging onto him, felt it vibrate through his chest, through his arms— through every nerve in his body.
Oh.
Oh, no.
Katsuki sucked in a sharp breath, then violently shoved Izuku off of him.
“Forget that happened.” His face was scarlet , ears flattened against his head as he stomped away from the scene of the crime. “ Forget it.”
Izuku, still sitting in a dazed heap on the kitchen floor, absolutely did not forget it .
------------------
Rubbing the towel against his hair, Izuku made his way back to the living room and stopped. (He had to shower again after the kitchen incident, but he wasn't complaining)
There lay Katsuki on the sofa, his eyes closed and breathing leveled as his skin soaked up the sun. His tail curled up against him.
Katsuki’s ear twitched. His nose scrunched up slightly, and then—his eyes cracked open, slowly, like he was waking from the best nap of his life. His gaze landed on Izuku, standing there in his damp towel, staring at him like he’d just seen something divine.
Katsuki stretched, his back arching, arms reaching high above his head. His tail flicked lazily behind him, muscles rippling under his shirt as he let out a deep sigh. Then, he blinked at Izuku. “What?”
Izuku swallowed. “Uh—um.”
Katsuki squinted at him, then sat up fully, rubbing at his face. “Spit it out, nerd.”
Izuku hesitated, shifting his weight from foot to foot before blurting out, “Can I have a hug?”
Katsuki stilled . His ears twitched.
“…No?” He said, sounding thoroughly confused.
Izuku pouted. “Why not?”
Katsuki crossed his arms. “Because that’s weird. ”
“No, it’s not!” Izuku protested. “We used to hug when we were kids!”
Katsuki clicked his tongue, looking away, but when Izuku softly asked again— “Please, Kacchan?”—his tail flicked once. Then twice.
Finally, Katsuki groaned, rolling his eyes. “Fine. Whatever. Come here.”
Izuku beamed and immediately stepped forward, wrapping his arms around Katsuki’s torso.
The moment he did, Katsuki went completely still. Izuku held on tighter, pressing against him, and—slowly—he felt Katsuki relax. His tail curled around Izuku’s waist, his chin resting against Izuku’s shoulder as he let out a breath.
Izuku smiled against him. “…See? Not weird.”
Katsuki huffed, his grip tightening ever so slightly. “Shut up.”
They stayed like that for a while, till Katsuki's phone buzzed, startling them both.
Katsuki grumbled as he fished his phone out of his pocket, still holding Izuku loosely with one arm. He glanced at the screen and sighed. Mina.
“The hell do you want?” he answered, still not moving away from Izuku.
Mina’s voice rang through the speaker, annoyingly chipper. “Good news, Bakugo! We talked to the villain, and your little kitty problem should wear off in a few days. Turns out it only lasts two weeks max!”
Katsuki blinked. “...That’s it?”
“Yep! You’ll be back to your normal, non-purring self in no time!” Mina giggled. “I bet Deku’s gonna miss it, though.”
Izuku stiffened in his arms. Katsuki felt it instantly.
“The fuck does that mean?” he snapped, ears twitching.
“Oh, nothing! Anyway, just wanted to give you the update! Byeee~!”
The call ended with a beep, and Katsuki sighed, shoving his phone back in his pocket. “Well. That’s that.”
He glanced down at Izuku, expecting some kind of reaction—maybe relief, maybe amusement—but instead, Izuku stepped away, his face unreadable.
“…You good?” Katsuki asked, brow furrowing.
“I’m fine,” Izuku said quickly, too quickly.
Then, without another word, he turned and walked straight to the guest bedroom, shutting the door behind him with a quiet click.
Katsuki stared after him.
“…The fuck?”
------------------
The door clicked shut, and Izuku pressed his forehead against it, exhaling sharply. His heart was pounding. He didn't even know why he reacted like that—okay, no, he did know, but he wasn’t ready to admit it.
The thought of Katsuki losing the ears, the tail, the quiet way he had softened over the past two weeks— it shouldn’t matter. Katsuki was still Katsuki. His feelings weren’t supposed to hinge on something so ridiculous.
And yet, the moment Mina had said “a few more days” —something in Izuku cracked.
A few days. Then it would be over.
Then he’d lose this side of Katsuki—the side that nuzzled into his touch without thinking, that flicked his tail when he was annoyed, that let himself be held without making a big deal about it.
Izuku groaned into his hands. Why do I feel like I’m losing something before I even have it?
His thoughts were cut short by loud, heavy footsteps stomping toward the room.
Shit.
Before he could brace himself, the door swung open with absolutely zero hesitation.
Katsuki stood in the doorway, arms crossed, tail flicking sharply behind him. His ears were pinned back, his expression unreadable—but his red eyes locked onto Izuku’s with laser focus.
"The hell is your problem?" Katsuki demanded.
Izuku tensed. " Nothing. "
"Like hell it’s nothing," Katsuki snapped, stepping closer. "You got all weird the second Pinky said my quirk’s gonna wear off. You didn’t even say a damn word and just left. "
Izuku refused to meet his gaze. “It’s nothing, Kacchan.”
Katsuki scoffed, irritated. His ears twitched. "Why are you acting like I just told you I was fucking dying? "
That was the last straw.
Izuku’s frustration, his confusion, his everything came spilling out before he could stop it.
"Because I don’t want you to change back!" he blurted out.
Silence.
Izuku froze, the words ringing between them like a siren.
Katsuki stiffened. His ears twitched, but he said nothing.
Izuku clenched his fists. His face felt like it was on fire , but it was too late to stop now.
"I like you, okay?" Izuku’s voice cracked slightly, but he pushed through.
"I’ve liked you for a long time, but you’re just so—so you, and I didn’t know if I ever had a chance, but then this whole stupid cat quirk happened, and you were just so—so—soft, and I—"
He was rambling. He knew he was rambling. He shut his mouth before he could embarrass himself any further.
Katsuki just stared at him.
The silence stretched unbearably. Izuku's pulse hammered against his ribs. He couldn’t tell what Katsuki was thinking—his ears twitched, his tail had gone still, and his face was unreadable.
Then, slowly— painfully slowly—Katsuki stepped forward.
Izuku barely had time to react before Katsuki grabbed him by the collar and yanked him down into a kiss.
Izuku gasped against his lips, his hands automatically flying to Katsuki’s waist. Katsuki’s grip tightened for a second, like he was making sure Izuku wouldn’t pull away, before he relaxed into it—his tail curling loosely around Izuku’s wrist, his ears flicking forward slightly.
By the time Katsuki pulled back, Izuku was breathless. His heart was going insane.
Katsuki’s face was slightly pink, but he scowled anyway, his tail flicking in irritation. “Took you long enough, nerd.”
Izuku let out a choked laugh, still dazed. “I—what?”
Katsuki rolled his eyes, but instead of answering, he nuzzled his nose against Izuku’s cheek. Izuku died on the spot.
“Fuck,” Katsuki muttered under his breath. “You really like this dumb quirk, huh?”
Izuku squeaked.
Katsuki smirked, pressing another quick kiss to the corner of Izuku’s mouth. His tail curled around Izuku’s arm again, this time on purpose. “Guess you should enjoy it while it lasts.”
Izuku huffed out a breathless laugh, his fingers tightening ever so slightly in Katsuki’s hoodie. “Yeah, I really should.”
For a moment, they just stood there, the quiet hum of the apartment settling around them. Katsuki’s tail flicked lazily, brushing against Izuku’s wrist, and Izuku sighed, letting his forehead rest against Katsuki’s shoulder.
“Guess I’ll have to get used to you without the ears and tail soon,” Izuku murmured, voice muffled against Katsuki’s hoodie.
Katsuki scoffed, but the warmth in his voice betrayed him. “You’ll live, nerd.”
Izuku only smiled, breathing him in.
“Yeah… I will.”