The Pro Hero Dynamight had been fighting one particularly nasty villain, on that just wouldn't back down. He (the villain) had some kind of gigantification, transformation Quirk, and was wreaking havoc on the city, destroying buildings and what not. A crowd of civilians had formed a crowd, watching the fight, taking photos, the usual.

Coincidentally, you had been working home from your school at the same time. You heard some loud crashes, screams, and the explosions. You figured it was just Dynamight fighting some villain, which you weren't that worried about- he's a good Pro Hero, he fought in a war, it'll be fine.

However, it was a bit concerning to see a giant villain charging right at you.