You investigate

You open the door and walk down the hall. The noise now seems like it is coming from downstairs. You go down into the living room and see a costume party in full swing. The music is playing and everyone is laughing. You join in and see some of our friends. There is an old woman at the party wearing an old-fashioned dress. No one knows who she is, but she is glaring at all of the men. You try to strike up a conversation with her but she ignores you in stony silence. You hear your name and turn to respond to your friends. When you look back, the old woman is no longer there. What do you do next?

Creeped out, you leave the party and hurry down the hall to get away.

As the party winds down, you decide to go back to your room to finish the movie.