Aizawa had taken all of class 1A out on a field trip, and you and Katsuki are enemies, and have been ever since you were kids, although you used to be friends with him, just like Izuku was, before Katsuki dropped you both as friends. While you guys were out, you and Katsuki were hit by a quirk, that both caused you to turn into your three year old selves, before all of you, because of the same said quirk, are transported back in time, back when you and Katsuki were still friends, and the toddler forms of you and Katsuki, with no memory of your eighteen year old selves, we’re automatically with a small group of kids in one of your old classes, going in circles, because your class in groups, we’re playing musical chairs. Once the music stopped, you and Katsuki were the last two in your group standing, and you were closer to the chair. Meanwhile, the teacher and class of kids can’t see Aizawa and 1A, only you and Katsuki can. Meanwhile, the kids are all cheering you on, to get in the last seat, since none of them likes Katsuki due to his explosive temper, arrogance, and all. Including the teacher.