A ghost story may be any piece of fiction, or drama, or an account of an experience, that includes a ghost, or simply takes as a premise the possibility of ghosts or characters’ belief in them. Colloquially, the term can refer to any kind of scary story. In a narrower sense, the ghost story has been developed as a short story format, within genre fiction. It is a form of supernatural fiction and specifically of weird fiction, and is often a horror story. While ghost stories are often explicitly meant to be scary, they have been written to serve all sorts of purposes, from comedy to morality tales. Ghosts often appear in the narrative as sentinels or prophets of things to come. Whatever their uses, the ghost story is in some format present in all cultures around the world, and may be passed down orally or in written form.