Pipes, also called Warp Pipes, are features present in most Mario games. Their main purpose is to provide characters with a way to get from one point to another in an instant. Some pipes are home to Piranha Plants.
In Mario Kart
In Mario Kart DS, Mario Circuit features a pipe tunnel and pipes with Venus Fire Traps inside that shoot fireballs at racers. Pipe Plaza makes a return. Mushroom Bridge had the pipes removed.
In Mario Kart Wii, pipes appear on Koopa Cape as both scenery and a stage feature. Pipes as hazards return on Mario Circuit 3, while GCN Mario Circuit retains the Piranha Plant-inhabited pipes. Peach Beach had the pipes removed.
Some courses feature pipes in the background as well.