Mansion Kart was a cancelled game set to be released the day after Luigi's Mansion 2 was (December 11 2007), for the Nintendo DS. This is not considered to be part of the Luigi's Mansion series, and is simply part of the Mario Kart series, although it has some items from the series.
Not much is known about the gameplay, except for that the Poltergust 5000 and Poltergust 3000 were supposed to be items, and the playable characters were characters from the Luigi's Mansion series. It was a racing game.
Nintendo decided to close this game a few months after the game was announced. The reasons listed were:
- Not enough characters
- Not enough items
- Not enough tracks
- The popularity of the recently-released Mario Kart DS
- Luigi's Mansion was already a track in Mario Kart DS
- The Poltergust 3000 was already a kart in Mario Kart DS, although it was known as the Poltergust 4000