Melon Bugs are little bugs that can roll into balls in Super Mario World 2: Yoshi's Island. They're called Melon Bugs because when rolled up the streaks across their body makes them look like a melon.
They bob up and down but when Yoshi gets to close they hide. Stay in the air when the bugs touch the ground and they'll keep jumping. Eat one and then spit it out so it will roll into and defeat any enemy.