A Piranha Plant is an enemy in the Mario series. The enemy is a large plant with a round head and a mouthful of teeth that will pop out of a pipe usually. His first appearance was in Super Mario Bros. where he would pop out of a pipe. These were green colored plants that wouldn't come out if the player stood directly next to the pipe. In Super Mario Bros. 2, a red variant was introduced. These were faster and would always pop out whether or not Mario stood next to or over a pipe. Though they are usually in pipes, they sometimes aren't, such as in Super Mario 64 where all the Piranha Plants are on ground.
In Super Mario World 2: Yoshi's Island, the player would have to throw eggs at his head a certain amount of times until he would die depending on what color he is. Some Piranha Plants can also shoot fire balls out of their mouths, and this type of plant is called a Venus Fire Trap.