Rhomp

Rhomps are a rolling species of Thwomp that first appeared in Super Mario Galaxy 2. They are only found in the sand slide area of the Slipsand Galaxy, where they attempt to flatten Mario, instantly depleting his health. They resemble tube-shaped stones with smiley faces and a circular stone with square designs on it attached to each side. They are similar to Spindels, sharing as well the almost same attack pattern.

Trivia
Both Mario and Luigi can leap over the Rhomps. If they touch the top of one, they will fall off the Rhomp without losing a life.