The world poltergeist derives from a german word meaning 'rumbling ghost,' which is widely believed to be a spirit or ghost that interacts with others by moving and influencing inaminate objects. Poltergeist phenomena is a focus of study within parapsychology, whereby parapsychologists define poltergeist activity as a type of uncontrolled psychokenisis.

Poltergesit activity tends to occur around a single person called an agent or focus. Focuses are often, but not limited to, pubescent children. Almost seventy years of reseacrh by the Rhine Research centre has led to the hypothesis among parapsychologists that the 'poltergeist effect' is a form of psychokenisis generated by a living human mind (that of the agent). According to researchers at the Rhine centre the poltergeist effect is an outward manifestation of psychological trauma. Skeptics beleiive that the phenomena are hoaxes perpetrated by the agents. Indeed many poltergeist agents have been caught by investigators in the act of throwing objects. However parapsychologists investigating poltergeists think that most occurences are real.

Another version of the poltergeist is the wrath version. When a person dies in a powerful rage at the time of death, the person is believed by some to come back to fulfill that veangance. In some cases the veangance is to strong to let go or forgive, and the metaphysical ghost becomes a poltergeist, in which the newly formed ghost can affect solid objects.