Inky Piranha Plant

Inky Piranha Plants are enemies first appearing in Super Mario 3D Land. They resemble normal Piranha Plants, but they are black instead of red and can spit ink.

Super Mario 3D Land
Inky Piranha Plants appear mainly in the underground levels. They spit ink out of their mouths to cover the screen, like a Blooper in the Mario Kart series. When the ink is on the screen, Mario or Luigi cannot see very well and might run into an enemy or a pit. If the player blows into the microphone, though, the ink will be blown off, removing it from the screen. They can be defeated by any attack method, just like a normal Piranha Plant.

Mario Tennis Open
Inky Piranha Plants appear in Mario Tennis Open. In Ink Showdown, a revamped version of the Piranha Challenge from Mario Tennis, they shoot tennis balls to the player, as well as ink blobs that will block their screen so it's harder to see.

Mario & Luigi: Dream Team
Inky Piranha Plants make their first appearance in the Mario & Luigi series as background enemies in Mario & Luigi: Dream Team. Inky Piranha Plants do not appear in the field due to their nature of a background enemy, and only randomly appears during battles against Fire Bros and/or Flaming Antasmatons in the later segments of Neo Bowser Castle.

In battle, Inky Piranha Plants will spit ink at the screen, just as in Super Mario 3D Land, making it difficult to see and avoid enemy attacks. Unlike most background enemies, it cannot be brought into the foreground whatsoever, and the use of a single Taunt Ball will simply knock it unconscious, rendering it unable to shoot ink for several turns. Once again, unlike most other background enemies who are defeated through use of a Taunt Ball, Inky Piranha Plants can be defeated if a total of three Taunt Balls are thrown at one by either Bro.

After an Inky Piranha Plant spits ink on the screen, it can be cleared off quickly by blowing into the 3DS microphone.

Mario Kart Live: Home Circuit
In Mario Kart Live: Home Circuit, a blue Inky Piranha Plant may appear on the trackside and squirt blue ink onto the player's screen, obscuring their view similar to a Blooper.

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

Trivia

 * Inky Piranha Plants were going to reappear in Paper Mario: Sticker Star, but were cut from the game.