Piranha Plant ("Pakkun"/"パックン" in Japan) is a Venus fly trap-like enemy, almost always portrayed as a leafy green stalk topped with a white-spotted red head, bisected by a white lip mouth with sharp teeth. They have shown up many times in the series, typically hide within pipes (sometimes pipes Mario can go into), and come out whenever something passes close by. Some species can also spit fireballs, called Venus Fire Traps. Others live entirely outside pipes, being either rooted in the ground or even walking about on root like legs. When Mario is standing on a pipe, they have the tendency to stay in the pipe. Piranha Plants originally appeared in Super Mario Bros., making them one of the first and oldest enemies in the entire franchise.
On the television series based on Super Mario Bros., Piranha Plants made various appearances, usually acting as obstacles for the heroes, much as they do in the games. In the Super Mario Bros. 3 cartoon, Venus Fire Traps and Ptooie Plants were used in a manner similar to guns. In Super Mario Galaxy, they would instead be planted in a flower patch and moves as far as it's stem will let it and try to attack Mario.
Piranha Plants first appear in this game on the very first level of Super Mario Bros.. They tend to pop out of Warp Pipes attempting to bite Mario or Luigi. In later levels, Piranha Plants tend to appear near areas where Mario or Luigi must time their jumps carefully before landing on the Piranha Plants. Piranha Plants in this game can be defeated with fireballs from Fire Mario.
In Super Mario Bros. 3, Piranha Plants act the very same as the did in the original except now there are a new species known as Venus Fire Traps. These new type of Piranha Plants can spit fire at Mario or Luigi with great accuracy. They can normally be defeated with the Fire Flower or any other damaging power up.
In Super Mario World, both current types of Piranha Plants are present in this game (Stemmed ones are actually very rare, Jumping plants are much more common). This game also introduces the Jumping Piranha Plants which can leap from their Warp Pipes and bite Mario or Luigi at great heights. Piranha Plants may also be perched on certain areas where Mario or Luigi must use a power up to take them out and safely cross.
In Super Mario 64, Piranha Plants can be found in the levels Whomp's Fortress and Tiny-Huge Island. In this game, the Piranha Plants are always found sleeping and a soothing song can be heard whenever they are sleeping. However, if Mario walks too fast, the Piranha Plant will wake up and start biting making it hazardous to go near. Mario can either move back until it goes to sleep or take it out with the nearby Super Mushroom (only for Whomp's Fortress). At Tiny-Huge Island, giant Piranha Plants can be found. During one mission, the Piranha Plants must be taken out in order to earn a Power Star from that level.
Piranha Plants are only found in the Pipe Vault of this game. The Piranha Plants act much like the did in the other games as being enemies in Warp Pipes. If Mario comes into contact with a Piranha Plant, it will engage him and his party in battle. The Piranha Plants use mainly Fire-elemental moves in this game and can be easily taken out with Mallow's Snowy move.
There are also two different types of Piranha Plants known as the Megasmilax and the Smilaxs which appear as bosses in this game. They are fought on Bean Valley and are extremely weak to Mallow's Snowy like the other Piranha Plants. The Megasmilax is capable of using the deadly Petal Blast move while the Smilaxs attack with simple bite attacks.
In Paper Mario, regular Piranha Plants can be found in the Jade Jungle. Out of the other variations including Putrid Piranhas and Frost Piranhas, the regular Piranha Plants are the strongest and can even attack with a poison bite. The Piranha Plants serve under the Lava Piranha who lived in Mt. Lavalava. It should be noted that all of the Piranha Plants in this game show their mouths forward instead of upward which means that Mario can jump on Piranha Plants without worrying about taking damage.
In Paper Mario: The Thousand-Year Door, Piranha Plants can be found in the Pit of 100 Trials. They attack the same as the previous game except now, their mouths are pointed upward and Mario cannot jump on them anymore (unless he is wearing the Spike Shield badge). The regular Piranha Plants are now the strongest type of Piranha Plant in the game having very high stats. The other types of Piranha Plants return in this game and a new type of Piranha Plant is shown known as Pale Piranhas. The Pale Piranhas are the weakest type of Piranha Plant in the whole game.
In Super Paper Mario, Piranha Plants can now attack freely at Mario and the others. The Putrid and Frost Piranhas can use distance attacks which can poison or freeze Mario and the rest forcing the player to shake the Wii Remote to break free.
In Paper Mario: Sticker Star, Piranha Plants are only present in World 3 and World 5 of this game. The Venus Fire Traps mainly appear in this game and are renamed "Fire Piranhas." They can attack by either biting Mario or spitting fireballs at him.