I had a nightmare last night and I wonder what it could mean.

There was a girl coming to me and she asked me if I wanted to help her to 'defeat' a certain man. He lived underwater, but his house wasn't filled with water. The girl told me not to look at him because his appearence would be so scary it could drive you insane. First I had to walk down a long stairs to get to his house. Then there were all of these shadows quickly moving around the room but there was no one in the room. Then right in front of me the scary man came down but I only saw his shadow against the wall. It was a very thin man with a long face and scary teeth.

That's where my dream ends, what could it mean?

I think the man is a part of you that you want to change, but maybe are a little afraid to.