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“You sure this is a good idea?” Izuku mumbled.
Katsuki stood in front of him, arms crossed over his chest. He wore his usual scowl, a brow raised, “I’m plenty sure, nerd. I’m not an idiot.”
Tonight was the full moon, and as a recently turned werewolf, Izuku couldn’t stop worrying. His fingers kept twitching and his eyes darted around the room. He’d been bitten only a week ago. Right after, he’d experienced blinding, white-hot pain. Then nothing. Blacked out and woke up in Katsuki’s bed with shredded clothes. Katsuki had chewed him out for getting himself turned into a giant dog and not being careful about being seen. Izuku hadn’t believed him at first, to which Katsuki proceeded to beat him with a pillow because, and quote ‘why the fuck would I lie about you being a stupid mutt hogging my bed all night?’ He’d had a point.
Now they stood in Izuku’s room. He fidgeted with his phone, constantly checking the time. The sun was meant to set in half an hour. His heart wouldn’t stop pounding.
“How are you sure it’s safe?” Izuku wrung his scarred fingers in his hands. “Werewolves aren’t known for being docile. What if I hurt you?”
Katsuki scoffed, rolling his eyes. “Believe me, even as a big ass dog you’re not much of a threat. You laid on my bed and passed out.”
“But what if it’s different this time?” Izuku argued, brushing off the off handed insult.
“I will beat your ass if you try anything funny. That put your nerd mind at ease?” Katsuki gripped Izuku’s shoulders.
Izuku bit his lip. His teeth were aching, the slightest ache in his legs making itself apparent. He sat down on the bed, Katsuki following suit. His voice softened just a fraction, “It’ll be fine, Izuku.”
“You promise?” Izuku’s big green eyes met his crimson, burning with a seriousness that felt foreign.
Katsuki nodded once, but he smirked, “Want to pinkie promise too or will you actually trust me?”
Izuku huffed, “Kacchan.”
“Izuku,” Katsuki’s grin widened as he teased him.
The sun sinking lower seemed to make Izuku shake more. He took a shaky breath. Katsuki grumbled, “I’ll be here the whole time, alright? Can’t let you tear up all your All Might fanboy shit. You’d be crying for weeks.”
“And you gave me some of it,” Izuku smiled up at him knowingly.
Katsuki’s face reddened. “Shut up.”
Izuku leaned his head against Katsuki’s shoulder, a small noise escaping his throat, “I’m scared, Kacchan.”
“I know,” Katsuki rumbled, slowly putting his arm over Izuku’s shoulder.
The affection wasn’t lost on Izuku and he melted into the touch. He closed his eyes, trying to keep his breathing even, despite the ache in his gums growing more apparent. He turned his face into Katsuki’s shoulder. An…odd feeling rising up in his stomach as he opened his mouth and bit down on Katsuki’s shoulder.
“Hah?” Katsuki flinched, glaring down at him and pushing at his head, “What the fuck? Nerd, don’t bite me! We don’t need two dogs in here!”
A growl rose from his throat and Izuku continued to chew on Katsuki’s shoulder. “Quit moving, Kacchan.” He mumbled around the fabric of Katsuki’s shirt in his mouth.
“You’re biting me, asshole!” Katsuki finally got Izuku off of him, who looked up with a distinctly kicked puppy pout.
Izuku grumbled, “It was helping. I hate how this feels.”
“I’m not your chew toy,” Katsuki poked Izuku’s cheek. “Find yourself a bone or something.”
“I’m not a dog!” Izuku protested.
Katsuki frowned, “You kind of are.”
The sun dipped below the horizon and the effect was immediate. Izuku yelped as a wave of pressure ran up his body. He pulled away from Katsuki, digging his fingers into his wild mess of curls, inhaling sharply.
“Breathe, Izuku,” Katsuki would’ve kicked himself for the way his voice wavered if he wasn’t overwhelmed with worry.
His teeth were the first to change, just like the first time. The memory of the agony was fresh in Izuku’s mind as the sharp sting of pain hit him like lightning. His canine teeth elongated as he groaned. Everything became too much. Sounds hit him like gunshots. Every beat of Katsuki’s heart was like a drum. Every breath, winds from a hurricane. He covered his ears, but his nose still assaulted him with the smell of sweat, dust, and fear.
Izuku crawled to the corner of the bed, pressing his back up against the wall. The bones in his fingers cracked and grew. His legs seemed to snap and be put back into place. Stronger, thicker.
Nausea rose from Katsuki’s gut, watching his best friend’s body stretch and the sharp sounds of snapping bones echo in the quiet room. Katsuki’s hand hovered in the space between them, his heart lurching in his chest to try and ease the pain. Izuku was doing remarkably well at staying relatively quiet while his body was being pulled like taffy.
Izuku doubled over, his ears had moved to the top of his head, elongating into fluffy canine ears. Another gut wrenching crack as Izuku’s skull literally broke and changed into a long snout.
Katsuki leaned over the side of the bed and vomited.
Once he wiped his lips, he looked up at Izuku again, who flopped forward on the bed, blood dripping from his nose. It seemed the gruesome change was over. Katsuki eyed him for a moment before he cocked his head, “Nerd? You good?”
Izuku didn’t reply, but his ears perked up. The viridian fur that covered his body looked shaggy and was ruffled in a few places. Katsuki rolled his eyes and he smoothed it out around Izuku’s shoulders where his shirt had been ripped. “You look stupid, you know that?”
The werewolf’s eyes flicked up to meet his and his thick tail began to wag. Katsuki gawked. “What?”
Izuku whined. Katsuki’s jaw only dropped further when Izuku scooted closer until his head was in Katsuki’s lap. “You’ve got to be fucking kidding me.”
Either Izuku was somehow conscious and gained a twisted sense of humor, or he was a giant mutt begging for attention from Katsuki.
“Fuck off. You’re not going to convince me,” Katsuki looked away.
Izuku shifted his weight, leaning forward to touch his cold nose to Katsuki’s middle. He flinched and flicked Izuku’s forehead, glaring at him, “No.”
Izuku growled and he sat up, looking down at Katsuki. His new height and bulk was incredibly irritating. Katsuki crossed his arms, “Don’t start throwing a tantrum or I’ll have to kick your ass.”
Izuku cocked his head, his ears flopping. He sniffed the air around Katsuki and his tail started up again, thumping against the bed. The mattress dipped under his weight. Katsuki pushed his snout away, “If you’re in there I will kill you for this, I hope you know that.”
The werewolf blinked and threw his weight onto Katsuki, making him flop back onto the bed. “Hey!”
Izuku’s ears lifted and to Katsuki’s horror, he began to lick his face. Katsuki groaned, “Izuku! Stop! God- fuck. Deku, god damn it! Stop that!”
Despite Katsuki’s pushing and constant shouting, Izuku wasn’t deterred. He didn’t stop until he was satisfied, laying his nose in between Katsuki’s neck and shoulder.
Katsuki shot daggers at him, “You are dead.”
Izuku happily snuggled against Katsuki, squishing him under the weight of Izuku’s giant form. Katsuki gritted his teeth and patted Izuku’s neck. His fingers tangled in Izuku’s fur mindlessly as he sighed, resigning to his fate. Izuku nudged Katsuki’s cheek with his nose.
“Demanding little shit,” Katsuki muttered but his nails scratched behind Izuku’s ears.
A tiny, traitorous smile pulled at his lips as he watched Izuku’s head lean heavily into his hand. His big green eyes were still so full of adoration and affection. Katsuki hugged Izuku closer and closed his eyes, dozing off quicker than he had in a long time.
-
Izuku woke up gently, the sun bringing warmth to his skin. He smiled, nestling into the subtle heat at his side. His eyelids cracked open and he was met with Katsuki’s soft face, lashes fanned over his cheeks. Izuku’s brows shot up. Katsuki was in his bed. Izuku was cuddling with his Kacchan. In his bed. Izuku slowly tried to sit up but was stopped by a strong arm around his waist that pulled him back down.
“Quit moving,” Katsuki mumbled. “Too early.”
Izuku silently obeyed and laid his head over Katsuki’s heart, listening to the steady beating under his ear. His senses might still be heightened because he could swear he smelled contentment coming from Katsuki.
Shit. That’s right. The full moon was last night.
“Kacchan?”
“Mm.” Katsuki grunted.
Izuku studied Katsuki, “You…last night. How was last night? Everything…everything went okay?”
There was no response for a few moments before Katsuki opened his eyes. Izuku’s breath caught in his throat. He looked beautiful like this. The sun was hitting his face at the right angle, the red in his irises lit up as light hit his cornea.
Maybe he had died. Maybe Izuku had gone berserk and Katsuki set off an explosion and killed him. It was the only reasonable explanation for the dream he found himself in.
“Fine,” Katsuki replied, his voice gruff with sleep. “You nearly crushed my ribs though.”
Izuku’s eyes widened, “I what?”
“You laid on me,” Katsuki replied simply. “Then licked my face, you dick.”
Izuku’s face burned, shrieking, “What?”
“You don’t remember that?” Katsuki narrowed his eyes suspiciously.
Izuku shook his head furiously. Katsuki’s face fell, almost looking disappointed. “Damn. I was going to kick your ass.”
Honestly, Izuku couldn’t blame him. He was mentally shaking himself. How could that happen? He couldn’t remember anything so clearly he wasn’t in control of himself, but still.
Embarrassment and shame had a blush creeping up his throat into his freckled cheeks. “I’m so, so sorry, Kacchan. I never, never would’ve done that if I was aware.”
Katsuki snorted. “Chill out, nerd. It was gross but it’s not like you bit my head off. Like you tried to do when you were still lucid.”
Izuku’s face only got hotter, “It helped! My teeth were killing me! I never would’ve actually broken skin!”
Katsuki ruffled Izuku’s hair, “Just shut up and go back to sleep.”
A smile worked its way onto Izuku’s lips and he laid his head down again, moving until he was comfortable at Katsuki’s side. Screw the awkwardness he’d inevitably have to deal with later. Kacchan was next to him, holding him, and he wasn’t going to let the moment go to waste.