Mr. Eraser

Mr. Eraser is an ally in Super Mario Maker and its sequel, Super Mario Maker 2, who takes the shape of an eraser with legs and eyes. His icon is placed on the right hand side of the level creation screen, under Coursebot. Upon his icon being tapped, the player is able to remove spawned enemies and objects. He has three official courses made by him. Super Mario Maker 2 will feature Mr. Eraser in the game's story mode, appearing for the first time as a 3D model.

As seen in the game's E3 2014 trailer, there was originally an eraser that had a letter "E" on it, similar to the one in Mario Paint, which had the exact same effect. This old icon was later replaced with Mr. Eraser.

Super Mario Maker for Nintendo 3DS

 * Digital manual description: "Mr. Eraser will wash away your mistakes. Simply tap this icon to activate the eraser, and then touch the element you want eliminated. Touch the eraser icon again to put it away."