Pocket Mirrors//Error sans x reader

You could always see the au's of the game undertale, The game wasn't in your universe, you couldn't leave your world but you could look at other universes, it was like a one-way mirror. You could see and hear what's going on but they couldn't see or hear you, no way to interact with them, either.

You always told yourself that this was just your active imagination, no matter how loudly that part of your head screamed that they were real, so what do you do when one of the skeletons finally sees you?