Boo

The Boo is an item that debuted in Koopa Kart 64 and also appears in several older Koopa Kart games, such as Koopa Kart Advance, Koopa Kart: Double Trouble!!, and Koopa Kart DS. It makes its most recent appearance in Koopa Kart Wii, as it does not appear in later Koopa Kart games as of Koopa Kart 7.