Choco Island 1 & 2
These Piranha Plants in Mario Kart 64 appear biting up and pull over if the player hits one. They are on the edges of the track.
Piranha Plants then appear in Mario Kart: Double Dash!! Mario Circuit, where there are a few of them on each side when turning a U turn, and they will bite you if you are too close to them. They also appear at the very end of the course. They acutally snap out at you, blocking your path.
They appear here as well! They appear in pipes (as in Mario Kart: Double Dash!!) and on the ground (as in Mario Kart 64). There are two that actually breath fireballs at you. This is the last time you see them in the Mario Kart games, unless you count Retro Stages.
They appear in the New Course Pirahna Plant Pipeway And for the first time it has It's own course.
They also appear in Yoshi Circuit almost everywhere now, and are harder to avoid.
Fake statued plants appeared in Falco Stadium. They seem to be made of wood and come out of pipes that are on their side in the halfpipe.
The Piranha Plants in Time Trials will not try to bite you because it is a Time Trial, and not Grand Prix, where it is fair to get hurt while in first, and no reason to get hurt while doing a Time Trial.