Idea for couple metal costumes that people will understand?

Hi! I need to find an idea for a costume, for me and by best friend, who are both metalheads. Problem is, we live in a school where everyone is boring and does not like metal. Do you have an idea for a couple metal costume that regular, boring people will understand? I was thinking kirk hammett and james hetfield, or ozzy and sharon, but he is not really into that. We have a pretty big budget and we could get two (non working) guitars for the day. Thanks very much!