Big Boo's Haunt is a level in the Nintendo 64 and Nintendo DS game, Super Mario 64 and Super Mario 64 DS, respectively. To access this level Mario must punch the largest Boo in the courtyard of Princess Peach's Castle. The Boo must be punched from behind. Afterwards a strange object will appear. Mario will jump into it. It transports Mario to Big Boo's mansion which he and his minions haunt. The Boo's occasionally act like poltergeists and pick up chairs and launch them at Mario. The mansion has 6 doors on the first floor and 6 on the second floor. When Mario reaches the balcony at the peak of the house, he must engage in a battle with Big Boo.
In Super Mario 64 DS (the re-make of the original game), Luigi is being held captive in the haunt and must be rescued by Mario. This fits in well because after being released Luigi can use power flowers to become invisible.