Rotten Mushroom

Rotten Mushrooms are purple, skull shaped mushrooms that appear in Super Mario Maker 2. They replace 1-Up Mushrooms when the night mode is activated. Unlike most mushrooms, Rotten Mushrooms actively pursue the player. Touching a Rotten Mushroom powers down the player, making it a hazardous obstacle. Their skull-like design and role as an "evil" counterpart to "good" mushrooms makes them comparable to the Poison Mushroom, Zombie Shroom, and Ghoul Shroom.

The Super Mario World sprite appears to be inspired by the face of the fireballs used by Bowser in said game.