Bakugo walked into class 1-A already feeling pissy. To almost anyone else, his present attitude would look identical to his standard resting bitch face and excessive personality, but Midoriya clocked that something was up as soon as his life-long rival walked through the door.
"Move it, horns and hair," Bakugo grumbled, shooing Ashido Mina and Kirishima off of his desk where they were perched, chattering away like songbirds. Kirishima shifted to allow Bakugo access to his seat but otherwise changed nothing. Kirishima and Ashido were having one of their classic nonsense arguments, viciously debating the merits of boxed SpongeBob Mac-N-Cheese over lasagna.
Bakugo squeezed his eyes shut, his face tensing into a grimace. Finally, it was too much for the boy.
"Shut it, you fuckwits!" Bakugo snarled. His two friends squawked in alarm as they were shoved off the desk. Feeling himself losing control, Bakugo abruptly stood and faced away from his classmates.
"Kaachan, no!" Izuku cried, reaching out to his childhood friend.
Bakugou Katsuki looked back over his shoulder, a wan smile drawn across his face. Then he turned into a pufferfish.
There was a long moment of dead silence. Then Todoroki pulled out his theory-crafting bulletin board, and said "You don't understand, this makes perfect sense."