River Piranha Plant

River Piranha Plants are a variant of Piranha Plant that, as their name implies, lives in rivers. They appear in New Super Mario Bros. Wii, New Super Mario Bros. U, New Super Luigi U, Super Mario Run starting from the version 3.0.4 update, and New Super Mario Bros. U Deluxe. They greatly resemble the Jumping Piranha Plant of Super Mario World in design, as well as real-life floating plants, like duckweeds and frogbit.

New Super Mario Bros. Wii
River Piranha Plants first appear in New Super Mario Bros. Wii, where they appear in World 5-1 as common enemies. When Mario is not around, they blow green spike balls like a Ptooie's method of attacking. When Mario approaches, they suck in and bring the spike ball to their lips and slowly blow it upwards to attack. Just like regular Piranha Plants, they can be defeated with fireballs or a Star. Hitting it with an iceball will also freeze it in place. The spike ball itself can be taken out with a shell or the Star, after which the River Piranha Plant will sweat and panic in place, unable to do anything.

New Super Mario Bros. U / New Super Luigi U / New Super Mario Bros. U Deluxe
River Piranha Plants reappear in New Super Mario Bros. U and its Nintendo Switch port as rare enemies that only appear in Fliprus Lake and Seesaw Bridge. In New Super Luigi U, River Piranha Plants appear in Spinning Sandstones and Fliprus Floes. Their behavior does not change.

Super Mario Run
River Piranha Plants appear in Super Mario Run starting with the version 3.0.4 update. In the World Tour mode, they only appear in the level Spike Bar Jungle.

Super Smash Bros. Ultimate
In Super Smash Bros. Ultimate, River Piranha Plants (just called River Piranhas) are mentioned briefly by Viridi during Palutena's Guidance dialogue for Piranha Plant.

Super Mario Run

 * Notebook bio: "This may look like a regular Piranha Plant, but they can move objects by blowing on them."