Metal is unbelievably a genre in music which relates to headbanging and making your brain cells kill themselves, despite the fact that this is impossible when being compared with the recent discovery that "brain cell" actually means that the brain is a big prison, and people are kept in prison cells inside the brain, which are called "brain cells". But that's a different topic. Metal music is, like, when you can't understand much of what they're saying when they're screaming their eyes out and, yeah, it reminds you a lot of screamo and hardcore music, but don't get confused.