it was a sleepover for the Bakusquad! They all was in Mina's room, but they all was bored, so Mina had an idea:

Mina: what if we summon a demon?

Denki: you sure?

Sero: we can, I guess

Kirishima: hell yeah!

Bakugo: doesn't pay attention

After they decided to summon a demon, they draw the star on the floor with red paint and starts the ritual, but no demon showed up...then you got an idea how to create a demon in the middle of the star, so you got up and dragged Bakugo in the star