in this case you belonged to the universe of kimetsu no yaiba. There was a "Universe" problem and other types of "people" appeared in your world.

You were walking through the butterfly farm when you heard screams, one voice you recognized and another you didn't. You approached out of pure curiosity and saw Sanemi and another boy who, according to what they told you, was called Bakugou.

The two seemed to be loudly complaining about something.