The term 'poltergeist' comes from German, meaning 'noisy ghost' or 'rumble ghost.' This type of haunting is characterised by physical manifestations rather than necessarily visual ones. Common poltergeist activities include unexplained noises (knocks, bangs, footsteps), objects being moved, thrown, or hidden, doors and windows opening or closing on their own, and lights or electronic devices malfunctioning. While sometimes associated with a specific spirit, poltergeist phenomena are occasionally theorised to be linked to the subconscious psychokinetic energy of a living person, often an adolescent, under stress (Recurrent Spontaneous Psychokinesis - RSPK). However, many cases are attributed to mischievous or troubled spirits.