Petey Piranha is a large Piranha Plant with petals on his head all around his chin. His first appearance is in Super Mario Sunshine, and since then he has gained much popularity and has since become a regular boss in Mario titles. Petey Piranha is thought to be a loyal follower of Bowser, but this is unknown.. It is quite likely that he is the ruler of his kind, as suggested by his Japanese name, Boss Pakkun, "Pakkun Flower" being the Japanese name for the Piranha Plant. He has multiple special powers that set him apart from normal Piranha Plants, including spitting Graffiti, flying and attacking with vines.

At the end of each battle with him, he is destroyed, but always seems to be resurrected to appear in another game (even being fought twice in Super Mario Sunshine). It is unknow how he does this. It is also unknown if it is any other Piranha Plants like Petey.