Peeves is not a ghost, or a half-dead spirit. Like someone else said earlier, poltergeists generally spawn in places where lots of people are, like a school of kids. Apparently the reason peeves was not in the movies is because the actors laughed to hard whenever he was on set, which disrupted the movie.

Is Peeves not a ghost?

The name 'poltergeist' is German in origin, and roughly translates as 'noisy ghost', although it is not, strictly speaking, a ghost at all. Unlike the overwhelming majority of his colleagues, Peeves has a physical form, though he is able to become invisible at will. ...

Why was Peeves not in the films?

Rik Mayall was due to have played Peeves the poltergeist in the Harry Potter movies but was cut from the franchise, it has been revealed. ... I played the part of Peeves in Harry Potter,” he said, adding he got sent off the set because the extras kept getting the giggles.