This is a spirit, usually mischievous and occasionally malevolent, which manifests its presence by making noises, moving objects, and assaulting people and animals. The term "poltergeist" comes from the German , "to knock," and , "spirit." Some cases of poltergeists that remain unexplained and may involve actual spirits. In other cases the phenomena may be produced by subconscious psychokinesis on the part of an individual.

Included in the most common types of poltergeist activities are the rains of stones, dirt, and other small objects; moving or throwing of objects, including large pieces of furniture; loud noises and shrieks; and vile smells. It seems that poltergeists have adapted to the development of technology. They are known to have caused interference in telephones and electronic equipment, and turning lights and appliances on and off. Some poltergeists are said to pinch, bite, hit, and sexually attack the living.

Generally poltergeist activity starts and stops abruptly. The duration of it may extend over several hours to several months; however, some cases have been reported to last over several years. The activity almost always occurs at night when someone is present. Typically the "agent," is an individual who seems to serve as a focus or magnet for the activity. In most cases the agent is a factor. The symptoms seem to be a haunting but may be caused by the agent without the knowledge that they are doing it. The agent is usually female and under the age of twenty that is going through stressful times or chemical changes in the body but that is not set in stone.