A ⓘ (from German "poltern", which means "rumble" or "make noise", and "geist", which means "ghost", "spirit" or "embodiment") is a spirit or ghost that is able to move and influence objects. Poltergeists are said to be invisible.
Poltergeists are said to bother only one person at a time. This person is called their "focus". They are said to only last a few weeks, then will move on to another target. Often poltergeists are reported around children and adolescents.
Some scientists think that poltergeists only exist in a person's head as a result of psychokinesis. They think that the "poltergeist effect" is a result of mental trauma.
There is a 1982 movie called Poltergeist.
In Harry Potter there is a poltergeist named Peeves. However, Peeves is not a classic poltergeist. He can be seen and does not focus on bothering just one person.
