From the Super Mario Wiki
Projectilia Ritebakatchia, a pseudo-scientific name corruption of "projectile" and the phrase "right back at ya.", is an enemy class in Super Mario World 2: Yoshi's Island and Yoshi's Island: Super Mario Advance 3. Enemies in the class Projectilia Ritebakatchia throw projectiles at a Yoshi. They can usually be defeated by normal means, but sometimes they cannot be eaten. Enemies in this class include Wild Ptooie Piranhas, Blow Hards, Ukikis with watermelons, and Lakitus.