Piranha Plant

A Piranha Plant, known as Packun Flower in Japan, is an enemy almost always portrayed as a leafy, green stalk topped with a white-spotted red or green globe and sharp teeth.

Character description
Piranha Plants are large, carnivorous plants encountered throughout the  series; Piranha Plants are seemingly based-off Venus Flytraps, eating anything that approaches them. The head of a Piranha Plant is most commonly either red or green with multiple other colors. Originally, Piranha Plants were found exclusively in pipes, either darting-out and biting anything near or remaining still and spitting fireballs. Currently, Piranha Plants can be found both in and out of pipes and their fire-breathing ability is now rarely used﻿.

As a special move
✅

A potted Piranha Plant can be summoned by as his down special move. When an opponent comes close to it, the Piranha Plant will bite at them, and opponents grabbed will then be thrown in Waluigi's direction. The Piranha Plant also has a hurtbox, allowing it to block certain attacks. After throwing an opponent, being attacked enough, or being active for a certain period of time, the Piranha Plant will go back into the pot and disappear.

According to developers, this Piranha Plant is Waluigi's pet, who is named Thaddeus "Chompers" DePlant.

As a stage hazard
On the stage in Super Smash Flash 2, a Piranha Plant may appear out of a Warp Pipe that appears in the large gap of the stage, biting any character that touches it. It can be defeated if attacked enough, though.

Adventure level
In Super Smash Flash 2, they may be one of the many enemies in the Adventure mode stage,. They appear in the beginning of the level in a pipe trying to bite the player.