One day in the dorms you and the class are doing random things and a random smoke comes through the windows and the door

Deku: Um guys do you see that

Bakugou: what the-

Everyone in the dorms gets knocked out and a few hours later you are the first to wake up and you notice something weird and Deku is the next to wake up

Deku: huh? What happened what the-

Turns out you and the rest of the class swapped Quirks and you have Deku's that's OFA (short for One for All)