Midoriya Izuku is adorable as hell, and everyone in 1-A (hell, probably the entire student body) knows this well.

Most doesn't realize how dangerous he can be, and most doesn't know that he wasn't dangerous in the sense that he could hurt, or snap, or was unable to really control his quirk until recently. No, he was dangerous because he doesn't realize just how adorable he is.

It was a fact that 1-A class was quick to learn. How adorable Izuku simply was was easy to see, and it was palpable the moment he stepped into the classroom. Big, curious green eyes darted around to take in information, curly hair sticking out at all sides in tangled mess of glorious stubborn bedhead, and his somewhat short stature screamed cute to anyone in vicinity, and most people were charmed instantly. This kid was a sunshine incarnate, that was something that everyone collectively agreed upon without even sharing a word. Only few people remained immune to his adorableness, and that included Bakugou (probably because of how long they'd known each other), Aizawa-sensei (it was a mystery as to why he's immune, or maybe he just hid it well), and All Might (mostly because Izuku was either a stuttering mess around him or he got too serious for his adorableness to break the surface and hit All Might with its full power. Not that he wasn't adorable when he was serious, but it kind of shifted; no longer the pure shine of the sunlight showered upon someone, but rather dulled sparkle that was muffled by his thoughts, intentional or not.) The teachers were spared mostly because Izuku would be too busy fanboying over them or because he'd focus on the lessons, and even then they weren't completely safe. As long as they were in Izuku's radius, as long as they're able to see him, no one is safe.

Seriously, the only thing able to compete for the most adorable thing in the world award would be… puppies and kittens, and other small ridiculously cute critters, and even then it would be a pretty tight contest. The only time that Izuku wasn't downright adorable was when he was mumbling to himself, and sometimes even then.

The first time they saw it in action was when Izuku turned to Ochako, gave her an utterly, ridiculously adorable smile that somehow managed to look apologetic, and asked, "Uraraka-san? I forgot to bring my pencil case. Is it okay if I borrow your pencil?"

"I would be happy to lend anything, Deku," Ochako all but vowed as she shoved her prettiest pencil and newest eraser to the boy.

Izuku smiled brightly and Ochako internally combusted. "Thanks, Uraraka-san! You're a lifesaver!" he said, and Ochako looked like her processor had frozen mid-process and she'd hit the error blue screen, sitting rigid in her seat and looking like she was trying to not scream, or cry, or melt outright to the floor.

Iida was the next victim. He asked Izuku's phone number, "just in case we need it, since we're in the same class", and the next thing he knew Izuku was staring at him with sparkling eyes as if he'd offered him the world, and it was all Iida could do to stop himself from screaming his words for the rest of their conversation. His voice climbed in volume all the same, and the entire cafeteria saw.

What made it almost insulting was how Izuku was completely unaware of this fact.

The rest of 1-A dismissed it at first when Ochako and Iida brought it up, but soon they saw for themselves just how lethal Izuku's adorableness could be. A simple smile brought Kouda to tears. Especially bright greeting rendered Ashido a bumbling mess. Kaminari nearly electrified Kirishima when Izuku laughed freely at his joke, and Kirishima couldn't even get mad because he was too busy trying not to scoop Izuku into a hug and declare that he would kill everyone and then himself if anyone ever hurt the sunshine child.

The only people not affected were Todoroki and Bakugou, because Izuku never really spoke to them. After the school festival, Todoroki fell right into Izuku's radius without any hope to ever drag himself out. He'd made valiant effort not to, but in the end Izuku's black hole of cuteness dragged him in, too.

Everyone in class wondered how Shinsou Hitoshi managed not to get dragged in, since he was able to keep a straight face whenever Izuku waved, or smiled, or beamed at him. They realized that he was as far gone as they were when they saw Izuku talking to him casually and he looked like he was internally screaming, his fingers twitching in a familiar way that made the 1-A class absolutely certain that he was restraining himself from squeezing Izuku's cheeks or ruffling his hair.

"How is he so cute?" Ochako nearly whined one day, when the class was nearly full but Izuku hadn't come in yet. "How is it even possible to be so adorable?"

"It's his smile, isn't it," Iida breathed. "No mortal can say no to that smile."

"He's supposed to weaponize his strength, not his cuteness," Jirou muttered. She was one of the only people able to stand against Izuku's weaponized cuteness, aside from Yaoyorozu and Tokoyami, though enough exposure would bring them down all the same. "How is he able to weaponize his cuteness. At this point he won't even need to activate his quirk. He can just politely ask a villain to give themselves up to the police and they'd comply."

"If it wasn't for the fact that we'd all seen him use his quirk, I would've thought this was his quirk, ribbit," Tsuyu remarked. "Although I don't think this kind of thing even counts as a quirk."

"Still, it's impressive that he's not even aware of this," Kirishima commented. He crossed his arms. "Oi, Bakugou. You've known him the longest and you seem like you can hold yourself against how cute he is. How'd you do it?"

"I can't, dumbass," Bakugou growled at him from his seat. "Why do you think I'm always angry around him? Pisses me off so much when he smiles; it derails my train of thought."

Ochako's own train of thought ground to a halt. "You're not… immune to it?"

"I don't even know who could be immune to it," Bakugou grumbled. "As far as I know it runs in the Midoriya family. His mom is about as bad as he is, and I've never seen my absolute hag of a mother even able to say no to her."

"Then… why are you like this around him?" Todoroki questioned. He sounded so perplexed that the class wondered how he could maintain a straight face.

"Stops him from smiling," Bakugou answered with a scowl. "He can't use it against you if he doesn't smile."

The class stared open-mouthed at him, trying to see how he could use that logic with Izuku's perpetual sunshine warmth around him. Maybe having known Izuku for so long helped built some kind of immunity after all, but not strong enough to actually completely reject Izuku's shine. Besides, he'd known Izuku's mom, so maybe the combined exposure helped him find a way around it?

The silent speculations stopped when the door slid open and Izuku slipped in. His eyes found Bakugou, and he skittishly walked ahead and called cautiously, "Kacchan?"

As usual, Bakugou glowered at him. "What?" he asked, callous.

"Well, um," Izuku rummaged through his bag and took out a box, neatly wrapped in sunny yellow paper and decorated with vibrant green ribbon. "It's your mom's birthday, right? My mom asked me to give you this, so you can give it to your mom. She'd give it to her herself, but work has been hectic lately, so…" He fidgeted. "Can you give it to her?"

Bakugou stared at him for a moment before snatching the gift. "Fine," he grumbled.

Izuku smiled in relief, and the sunshine poured out of him mercilessly. "Thank you, Kacchan!" he beamed, and the class could see how Bakugou twitched, how his face flushed. They'd mistaken it for anger before, but they knew better now. "Ah, also, Kacchan? My mom wanted to invite you and your family for a dinner in our place this weekend. She said it's been so long, and she'd love to have someone over. Do you think you can make it?" he fidgeted again, eyes sparkling with hope.

Bakugou's eyes twitched and he clicked his tongue, looking away. He took a deep breath and huffed in clear surrender. "Probably," he said at last. "I'll have to ask the old hag first, though."

Izuku beamed again. "Okay," he said, hands finally stilling. "Maybe your mom can call mine to confirm things?"

"Don't tell me things I don't already know, shitty Deku," Bakugou lashed. "Of course she'll call. Have the hag ever not call your mom when she asks?"

"R-right, sorry," Izuku squeaked and took a step back. "Thanks, Kacchan."

"Get the fuck out of my face," Bakugou growled, and Izuku hurried to comply. He didn't see the way Bakugou hung his head low and huffed a longsuffering breath.

"Incredible," Ochako whispered in awe by the side. "Even Bakugou isn't exempt from it."

"There's probably no one who's safe from it, then," Todoroki commented quietly. Anyone who heard it nodded in agreement.

Toshinori trod into the teacher's lounge, feeling faint. Young Midoriya had smiled so brightly at him from across the room that he felt like he was staring at the sun and wished him a good morning, and only years of carefully keeping his expression stopped Toshinori from breaking into tears. Somehow, he managed to smile back and wished the same for Young Midoriya, and the student flushed, both shy and happy, and Toshinori wondered how he was the one graced with such an adorable act and Young Midoriya was the one acting as if he'd been gifted with a thousand excited puppies.

How could he only just now realized the extent of his successor's cuteness? This late in the game, when the kids were already moved to dorms, instead of at the start when they were prowling around cleaning the beach?

"Oooh, I know that face," Present Mic commented with a grin when Toshinori plopped down to his seat. "It's Midoriya, isn't it? You just got a face full of the Midoriya Effect, right?"

"The what?" he couldn't help but ask.

"The Midoriya Effect," Present Mic repeated. "It's when he gets so adorable you can't bring yourself to say no to him."

"Is that what we're calling it now?" Toshinori asked with a grimace – it wasn't hard to pull off, considering he was in his less healthy looking form. "I suppose, yes. He greeted me at the hall."

Present Mic took a hissing breath and shook his head. "I swear, he gets more and more adorable lately. He used to be so shy around the pros but now he's used to us and he always smiles a greeting. Did you know Midnight had to fight the urge to put him to sleep and kidnap him somewhere?"

Toshinori stared. "She wanted to what."

Present Mic waved him off, as if he didn't just tell Toshinori that a pro hero had wanted to abduct his successor for being too cute. "It's a thing all teachers have gone through," he assured. "That kid is just too adorable for his own good."

"Well, I suppose – " Toshinori was interrupted by a loud meow from beneath Aizawa's desk. He paused a peered down, and was soon greeted by a pair of glinting yellow eyes that blinked innocently at him. He stared as the cat meowed again and walked out, jumped up to Aizawa's desk, and started licking its hind leg as if it owned the place.

"There you are," Aizawa's voice reached Toshinori's ears and the ex-hero watched as Aizawa lifted the orange tabby and expertly cradled it in his arm. "Don't just run off like that, Miu. I haven't even introduced you to everyone yet."

"Introduced?" Toshinori repeated, bewildered.

Aizawa blinked at him owlishly. "I overheard the kids wondering about a class pet. It's not against the rule, and having something they can take care of together in the dorms may help with the boredom. It's better if I just bring something that's already at least somewhat trained than if they somehow got their hands on an unruly stray."

"Yes, yes, don't forget the fact that Midoriya finds cats cute," Present Mic commented with a grin.

Aizawa's silent, withering gaze was an answer all on its own.

A/N: First attempt at writing a fic for BNHA, hope i did good. Also, this was posted with minimal editing, so I apologize for typos and stuff. I honestly wrote this because I can't get over how adorable Izuku is. It's ridiculous how cute he is. How can anyone say no to him. Also, it's not a quirk, and both Izuku and Inko have the same too-adorable-to-say-no-to trait and both are obliviously unaware of it.

Bonus scene:

Shigaraki: i need to kill that boy, kurogiri

Kurogiri: calm down, shigaraki tomura, we need to plan carefully if we want this to go flawlessly

Shigaraki: you don't understand he's so adorable i might say yes if he asked me to give myself to the police, he's dangerous

Kurogiri: doesn't mean you can just go guns blazing at him, you'll end up in jail

Shigaraki: he's so cute i hate him