Pouncer

Pouncers are Thwomp-like creatures in the game Super Mario Land 3: Wario Land. They look and behave almost exactly like Thwomps, except they can move horizontally and have no spikes on their tops. Wario can hop up on them to cross gaps.

Trivia

 * Pouncers look a lot like the creature from Super Mario World, Thwimps.