It was a relatively calm afternoon in the 1-A common room. The soft hum of chatter and the occasional burst of laughter filled the space. Mina, Jirou, and Yaoyorozu were huddled on the couch discussing something on Mina’s phone. Kirishima and Sero were locked into a fierce video game match on the big screen, shouting playful insults back and forth. Midoriya sat on the floor, legs crossed, scribbling rapidly in his hero analysis notebook. Bakugo grumbled from his corner, arms crossed, pretending not to care while clearly listening to everything.

Among all this, you — Shota Aizawa’s 7-month-old baby — were happily plopped down on a soft blanket in the middle of the room, surrounded by colorful toys. A little stuffed All Might, a jingly cat ball, and a teething ring kept your curious little hands busy as you giggled and babbled softly.

Aizawa, lounging on a beanbag with a steaming cup of coffee in hand, kept a close eye on you. His usual tired gaze softened whenever he looked your way, warmth tugging at the edges of his typically stoic face. That’s when Denki Kaminari walked in.

He had a mischievous sparkle in his eye and one hand tucked suspiciously behind his back. Trying his best to be stealthy, he tiptoed across the room towards you with exaggerated care, a small vial-shaped baby bottle in hand. It glowed faintly with a strange, shimmery liquid.

Denki: “Drink up, little baby…” he whispered while grinning.

You looked up at him with innocent, curious eyes and reached for the bottle, mistaking it for your usual milky treat. Giggling, you grabbed it with both hands and began to drink without hesitation.

Aizawa’s eyes narrowed instantly. Something didn’t feel right. He bolted upright, the cup of coffee nearly flying from his hand.

Aizawa: “WHAT THE HELL ARE YOU GIVING TO MY BABY?!”

The entire room froze.

Heads whipped around as gasps echoed through the common room. Midoriya dropped his notebook. Mina’s jaw hung open. Kirishima paused the game mid-match. Even Bakugo stood up with a scowl, clearly ready for a fight if things escalated.

Aizawa was already at your side, snatching the strange bottle from your hands and pulling you gently into his arms. He cradled you against his chest, inspecting you for any signs of harm. You blinked up at him, confused, and gave a little hiccup.

Denki: “W-Wait! It was just a prank! It’s harmless, I swear! It was just a tiny bit of joke potion from Mei! It just makes their voice super squeaky for like… a minute!” he nervously raised his hands

Aizawa’s eyes were glowing red with fury as his capture scarf twitched at his side.

Aizawa: “A prank?! What if it wasn’t?! What if it had a side effect? What if it hurt them?! You do not experiment on a baby, Denki!”

Denki shrank back, sweat trickling down his face.

Denki: “I-I didn’t mean— I thought it would be funny— I didn't know you'd—”

Aizawa turned slightly away, holding you securely in his arms as he gently rocked you, checking your temperature with the back of his hand and listening to your tiny heartbeat against his chest.

You, meanwhile, giggled suddenly—in an adorably high-pitched chipmunk voice.

Everyone blinked. You giggled again, this time sounding like a squeaky toy. Mina burst out laughing. Kirishima choked on air. Even Bakugo let out a weird bark of a laugh before quickly covering his mouth.

Aizawa: “…You’re lucky that’s all it did.” he groaned, but still pissed.

He glared over his shoulder at Denki one last time.

Aizawa: “But you’re on clean-up duty for the rest of the month. You prank my kid again, I’ll let Hound Dog handle your punishment.”

Denki gulped and nodded furiously as Aizawa gently kissed the top of your head, still glaring at the world with the protective rage of a sleep-deprived father.

You simply giggled again—

“EEEE-hee-hee!”

—in that squeaky chipmunk voice that would haunt Denki’s dreams for weeks.