When used, Piranha Plant spits a spike ball out of its mouth and keeps it airborne by blowing on it, with the ball rising and falling periodically. Piranha Plant will continue to blow on the ball until either it is launched in a direction, or the player stops holding the button at which point the ball will be swallowed. Piranha Plant can fire the ball left or right, and if the player launches it while it is at its lowest point, it will travel further than normal.
The spike ball has transcendent priority. Furthermore, the move stalls Piranha Plant's descent if used in the air. These traits make the spike ball an incredibly deadly edgeguarding tool. However, its damage decreases each time it hits an opponent and it will deal no damage at all should it hit the ground.
The spiked ball spit, when timed on a certain frame of the landing animation, can perform advanced techniques such as spitting the ptooie, but doing the swallow animation (known as a “Spallow”), or to do the spit animation while the ptooie just drops under the Piranha Plant; bypassing all soft platforms and becoming a deadly edgeguard tool against linear recoveries on stages such as Kalos Pokémon League.
The name is a reference to the Ptooie enemy from Super Mario Bros. 3. When encountered, Ptooies blow on spike balls to keep them suspended in the air, occasionally blowing on them harder to raise them higher. The Japanese name of the attack is the same name of the spiked balls that both Ptooies and Spikes spit out, being one of the several Japanese names for Mario enemies derived from Jugemu.
The Ptooie is also referenced in Palutena's Guidance when performed for Piranha Plant, in addition to other types of Piranha Plants.