Peeves is a poltergeist who haunts Hogwarts. Peeves is often "chased" by Argus Filch, who is a Squib, trying to make him quit whatever he is doing. In the beginning Peeves seems useless, but in the last book, Deathly Hallows, he proves himself trustworthy when throwing dung bombs at the Death Eaters. Being a poltergeist, Peeves is a spirit rather than a physical being, but very different from the ghosts for which he is occasionally mistaken. Peeves is capable of flight and can choose whether to be physically tangible. However, he is usually observed to take physical form. Peeves is able to manipulate objects, a trait not generally possible with ghosts, but common to poltergeists. Peeves's existence is essentially the embodiment of disorder, where he is observed to constantly cause it. In appearance, he is a small man with a mischievous face, a wide mouth, dressed in vibrantly coloured clothing. He derives joy from disaster and mischievous acts, usually causing disruptions rather than being violent and dangerous.
Peeves only listens to a select few: Dumbledore, the Bloody Baron, (whom he fears,) in the second book Nearly Headless Nick, and by the the fifth book Fred and George Weasley. Argus Filch, who is usually left with cleaning up the mess and damage Peeves causes, is his nemesis and works continuously to try to get Peeves thrown out; however, Rowling has stated in an interview that not even Dumbledore would be able to rid Hogwarts of Peeves forever. Peeves is, however, vulnerable to some magic; in Prisoner of Azkaban, Professor Lupin uses magic to teach Peeves a lesson by making the gum Peeves was stuffing into a keyhole shoot back out and up the poltergeist's nose. In Harry Potter and the Half Blood Prince, Harry uses magic to glue Peeves's tongue to the roof of his mouth, after which Peeves angrily departs.
During Dolores Umbridge's attempts to take control of Hogwarts in Order of the Phoenix, Peeves shows his loyalty to Hogwarts, and his destructive tendencies shift into overdrive as he goes on the rampage at the Weasley twins' request. When Umbridge attempts to sneak out of Hogwarts, Peeves chases her out, whacking her with Minerva McGonagall's cane (which she lent to him for that purpose) and a sock full of chalk. Peeves is depicted in Deathly Hallows twice, first where he aids the defenders of Hogwarts by dropping Snargaluff pods on the heads of attacking Death Eaters, and second singing a victory song for Harry at the end.
Rik Mayall was cast as Peeves for film adaptation of Philosopher's Stone. However, his scenes were cut from the final film and have yet to be released publicly (being omitted even from the deleted scenes section of the DVD release). Peeves was subsequently omitted from the Potter films that followed, though he can be seen in the Harry Potter video games. Peeves is also referenced in dialogue in the Queen's Handbag short film.