Everyone knows about nightmares, but they might not know that a "night mare" is a demon in Norse mythology that sits on a person's chest and makes them have frightening dreams. That's pretty scary! Readers will be thrilled to learn about more supernatural beings known to haunt homes and terrify people, such as poltergeists and even vampires. The only things spookier than these tales are the imaginative illustrations that make these creatures seem almost real.