Flophopper

Flophoppers are bug-like species of enemies introduced in Super Mario 3D Land. They are sub-species of Swaphopper, but unlike their cousins, they do not attack by using gravity tactics. Instead, they attack by moving around in a set area by flipping themselves around (much like a Bramball). They cannot be attacked while their spiked helmet is exposed, so Mario must wait until they flip and their underside is exposed which is vulnerable to a jump attack (this same vulnerability is shared with Swaphoppers). They can also be defeated by Fire Mario, Boomerang Mario, or Tanooki Mario.

Flophoppers are planned to make a return in New Super Mario Bros. U, their first appearence in the side-scrolling games. They'll probably act the same as in Super Mario 3D Land.

Trivia

 * Their name is a pun of flip-flop, referencing how they flip around, and "grasshopper".