"That's a Burt. An odd-looking pants wearing thing with a totally bouncy head. Max HP is 8, Attack is 2, and Defense is 2. If there's two or more, the one in the back will bounce along the others to gain enough height to bodyslam you with more force, so watch out! Regular jumps won't work on them so try a spin jump."

So here's Burt from Yoshi's Island, one of the more weirder designs from the game. I kinda modeled this a bit after Wonky, as he resembles the Burt enemies in a way. Maybe he's related?

As a bonus, here is "Dark Burt" for the Pit of 100 Trials.