Fire Nipper Plant

Fiery Walking Piranhas, also known as "Walking Ptooies" , are rare fire-breathing versions of Nipper Plants.

Super Mario Bros. 3
In Super Mario Bros. 3, only one appears in the entire game, near the end of World 7-8. Once it spots Mario it will attack him by spitting fireballs similar to Venus Fire Traps, though a Fiery Walking Piranha can shoot up to four fireballs at once.

Mario & Luigi: Dream Team
Fiery Walking Piranhas appear as background enemies in Mario & Luigi: Dream Team. However, they are referred to as "Nipper Plants". In battle, a Piranha Plant may spit out Nipper Spores into the background, each one instantly becoming a Fiery Walking Piranha. Once created, they shoot fireballs at Mario and Luigi individually, which they must deflect with his hammer to avoid taking damage and to also randomly hit the Piranha Plants in the process.

Occasionally, a Piranha Plant will spit a fireball towards the Fiery Walking Piranhas, who will bounce the fireball about until each Fiery Walking Piranha has touched the fireball at some point, where the last Fiery Walking Piranha to touch it sends the fireball towards Mario, who must hammer it back at the Piranha Plant who created it to counter-attack and avoid taking damage. The Fiery Walking Piranhas are defeated when the Piranha Plant that spawned them is defeated.

Super Smash Bros. Ultimate
In Super Smash Bros. Ultimate, Fiery Walking Piranhas are mentioned briefly by Viridi in the Japanese Palutena's Guidance dialogue for Piranha Plant. They are not mentioned at all in the English version.