When one is face-to-face with an extreme black hole (why one would be face-to-face with an extreme black hole is a subject of another article), looking at its ‘head’ and admiring its ‘hair’ seem like the last things one should be doing – trying to avoid being sucked into its ‘mouth’ would be tops on this writer’s list. Yet a new study suggests that the first thing one should do when confronting a black hole is to look for hair, because that will identify it as being ‘extreme’. What is an extreme black hole, why does it have hair and who is brave enough to give it a trim?