Peeves

In addition to the numerous ghosts that inhabit Hogwarts, there is also a famous and disruptive poltergeist. In the Harry Potter universe, Peeves is the most infamous poltergeist in British history and has “lived” at Hogwarts since 993. Many students and teachers enjoy Peeves, but he is a “pet peeve” for the caretakers at the school who have to clean up his messes. According to Pottermore, there has been many efforts to get rid of Peeves. The most recent (and most calamitous) was in 1876 when the caretaker at the time set a trap baited with weapons he figured Peeves wouldn’t be able to exist. Peeves, of course, managed to steal all the weapons (including cutlasses, crossbows and a cannon) and proceeded to go on a rampage. He only calmed down when school administrators signed a contract with him that allowed him one free swim in the boy's lavatory every week, as well as a new hat.