Boo Pipes

The Boo Pipes is King Boo's unlockable kart in Mario Kart: Double Dash!!. It is a gray version of Petey Piranha's Piranha Pipes, and can be unlocked by completing the Special Cup in Mirror Mode.

Unlike most heavyweight karts, the Boo Pipes is unique for having traits similar to that of a lightweight kart; low top speed and high acceleration. But unlike the lightweight karts, this kart is heavy enough to rival the weight of the Koopa King and Piranha Pipes. It is one of the four "out of the ordinary" karts, along with Green Fire, Turbo Birdo and the Barrel Train.

Because of these unique traits, the Boo Pipes is a popular choice among professional players.