The Ghostly Galaxy is an area in the Wii video game Super Mario Galaxy. Mario will find this area in the Observatory's kitchen. As its name implies, this is the haunted location in the game, and thus features plenty of undead species and characters such as Boos and the dreadful Bouldergeist, the boss of the area.
Mario will venture through this level not only to search for power stars, but to also find his lost brother Luigi. Once he does, the green-clad hero will give Mario a star, and the two will head back to the Comet Observatory. Mario will also come into possession of, for the first time, the Boo suit, which will ultimately turn him into a Boo. It is one of the few galaxies which has Boo mushrooms.