Luigi's Mansion is King Boo's base of operations in the game Luigi's Mansion. Before Luigi arrives, Mario is kidnapped here by King Boo while checking out the place firsthand when Luigi surprisingly wins a mansion in a contest he didn't even enter. In the beginning of this adventure, Luigi arrives late at the mansion and meets Professor Elvin Gadd who gives Luigi the Poltergust 3000 to assist him to hunt for ghosts and rescue Mario from what's really happening deep inside the haunted mansion. In the end of the game, the mansion is converted into a house that Luigi would now live in depending on how much loot you collected throughout the game.
Luigi's Mansion appears as an arena in Super Mario MHL.
Luigi's Mansion appears as a stadium in Mario Baseball All-Stars.
Luigi's Mansion is a court in Mario Basketball: Mushroom Tourney.