Grindel

Grindels are enemies that debut in Super Mario 64. They appear as mummified Thwomps, each with a pair of small round eyes and a grin on its face (hence the name). Compared to Thwomps in the same game, they are a more perfect cube shape and appear to be made of a darker, metallic stone under their wraps.

A similar creature is the Spindel, which look very similar to Grindels but are instead cylindrical.

Super Mario 64 / Super Mario 64 DS
In Super Mario 64 and its Nintendo DS remake, Super Mario 64 DS, Grindels appear only inside the pyramid in the level Shifting Sand Land. They attack in the same way as a Thwomp, floating up in the air vertically and falling over the ground, squashing anybody below them. Grindels can also move horizontally by jumping back and forth. In the remake, they have whiter teeth.

Mario Party 2
Grindels also appear in Mario Party 2 in the minigame Lava Tile Isle. Here, seven Grindels form a platform over a pool of lava. Before they change positions, they slowly shake. When they do move, they leave gaps between them (characters do not remain on Grindels when they move), and characters may fall into the lava.