Peeves

Peeves is a poltergeist living in Hogwarts, a fictional setting in the Harry Potter books by J. K. Rowling. He's a spirit rather than a physical being, but highly different from the ghosts he's occasionally mistaken for. Peeves is essentially an embodiment of disorder ("an indestructable spirit of chaos" according to a FAQ on Rowling's website), and is constantly causing it, with varying amounts of mischievousness and malice. In appearance he's a small old man dressed in wildly coloured clothing. He's capable of flight and intangibility, like ghosts, but can also affect solid objects and make himself invisible.

He's usually far more annoying than legitimately dangerous, but acts in a wildly unpredictable manner and should not be given the chance to cause serious harm.

Peeves does not listen to Hogwarts prefects (to Percy Weasley's great displeasure), teachers or anyone else, with the exception of the fearsome Bloody Baron for some unknown reason. Argus Filch, who is usually left with cleaning up the mess and the damage Peeves causes, is his nemesis and works continuously to try to get Peeves thrown out.

A scene with Peeves was filmed for the movie version of Harry Potter and the Philosopher's Stone, but was left on the cutting room floor. He has otherwise not appeared in any of the movie adaptations so far. It is rumored, however, that an extended "director's cut" of the first film, which would restore Peeves' sequence, is in the works for video release in 2005.

Peeves is not completely chaotic or without loyalties. During Dolores Umbridge's attempts to take control of Hogwarts in Harry Potter and the Order of the Phoenix that were met with passive insurrection, he actually showed respect for his fellow troublemakers Fred and George Weasley and took their words ("Give her hell from us, Peeves.") to heart as they fled the school, marking possibly the only time Peeves ever obeyed a student.

This was immediately followed by his finest hour, as he went into overdrive and began a rampage of ceaseless mayhem, juggling burning torches over the heads of students, dumping a bag of tarantulas into the Great Hall, and destroying property like never before. It appears that Peeves was actually on friendly terms with the strict Professor McGonagall during this time, due to their common enemy.