© Shutterstock

What is a poltergeist? -

According to Metro, the term derives from two German words: "Poltern," which means to make noise, and "Geist," which means ghost.

© NL Beeld

How does it happen? - The name is associated with paranormal phenomena like banging, moving objects, or even spontaneous combustion.

© iStock

The explanation - These activities are attributed to mocking spirits or demons.

© iStock

Theory - One theory is that ghosts are actually disturbed spirits who use the energy around them to become known. They also manifest when they notice changes in the environment, Metro explains.

© iStock

Differences - But what are the differences between poltergeist activity and a regular haunting?

© iStock

Differences - Hauntings are usually linked to a place or to ghosts that inhabit certain spaces. Poltergeists usually affect specific people.

© iStock

Phenomena -

According to The Paranormal Society, each phenomenon can begin subtly, and then become more intense with voices and apparitions featuring.

© NL Beeld

Targets? - The Paranormal Society adds that poltergeist activity is usually associated with the presence of an adolescent girl.

© Shutterstock

Targets? - When the person associated with the activity is removed, the activity usually stops.

© iStock

Science - Some studies associate these poltergeist with psychokinesis, which is the ability to move things by the power of the mind, The Paranormal Society reports.

© Shutterstock

Supernatural? -

Some people believe that poltergeist activity is associated with disturbing spirits, says Live Science.

© NL Beeld

Possession -

Cases of possession by poltergeist energy have been reported. The person usually isn't aware of the event, Metro reports.

© NL Beeld

Exorcism -

Metro further states that exorcism techniques are used to remove a poltergeist. This is usually a time-consuming and difficult process.

© Shutterstock

Poltergeist -

The poltergeist phenomenon has been portrayed in many movies and some of the behind-the-scenes stories are pretty scary.

© NL Beeld

Classics - These movies became horror classics but also caught the public's attention for the macabre stories that followed filming.

© NL Beeld

Real cases -

Coincidentally or not, many actors died after shooting supernatural movies.

© NL Beeld

Poltergeist -

The movie 'Poltergeist' was released in 1982 and told the story of a family being tormented by poltergeist activity.

© Getty Images

Tragic episode -

The first tragic event happened the same year the movie hit the theaters. Dominique Dunne, who played Dana, was strangled to death by her boyfriend.

© Getty Images

Second movie -

'Poltergeist II: The Other Side' was released in 1986, and another tragic event took place that year.

© NL Beeld

Tragic episode - Actor Julian Beck, who played Reverend Henry Kane, died from stomach cancer months before the release of the second film.

© NL Beeld

Tragic episode - A year after the movie premiered, another cast member died. Will Sampson reportedly died of a heart attack.

© iStock

Third movie - But the darkest story happened shortly before the third film, 'Poltergeist III,' hit the big screen in 1988.

© NL Beeld

Main character -

The most-remembered character in the trilogy is undoubtedly Carol Anne, played by the young actress Heather O'Rourke.

© NL Beeld

Tragic episode - Heather O'Rourke died at the age of 12, just before the movie debuted in theaters.

© NL Beeld

Tragic episode -

She died of cardiac-pulmonary arrest and septic shock, due to an undetected intestinal blockage, People reported at the time.

© NL Beeld

Curious fact - Drew Barrymore auditioned to play the role of Carol Anne, according to the Independent.

© Getty Images

Poltergeist curse - The tragic stories surrounding the film franchise became known as the Poltergeist Curse. Oliver Robbins, who played Robbie, says the curse is nothing but a myth, reports the Mirror.

© NL Beeld

Poltergeist: new version -

In 2015, another version of 'Poltergeist' hit the big screen. The movie directed by Gil Kenan tells the story of a family tormented by spirits.

© NL Beeld

Explanation -

Mind power? Spirits? Demons? Imagination?

What do you think poltergeist activity really is?

See also: Helpful ghosts from around the world 

© Shutterstock