The Ancient Poltergeist is a sub-boss in Luigi's Mansion Dark Moon. It has 150HP and is visually similar to a normal Poltergeist, only with a cobalt blue body and a cyan brain. It attacks by throwing bricks at Luigi, which deal 10 HP of damage if hit. Once Luigi drains around 30 HP of its health, the Ancient Poltergeist will hide in the turntable below and create a large tornado that has significant pull force and will damage Luigi greatly if he is pulled in. The Ancient also summons Sneakers to attack Luigi. It is the third mini-boss that is a Poltergeist, with the normal Poltergeist being the first and the Strong Poltergeist being the third.
- The Ancient Poltergeist was never seen in any trailers for Luigi's Mansion Dark Moon and Nintendo or Nintendo Power never mentioned anything about the Ancient Poltergeist. People found out about him when they find him in the game.