Punkey the Pokey Prince
From the Super Mario Wiki
He attacks by spitting Pokey Poms and ramming into Yoshi. The player can hit him by hitting his segments with eggs in order when spikes are not protracting from them. When Yoshi hits his head, Punkey turns angry and starts drilling into Yoshi and eventually calms down but adds one more segment to his body. When hit once again, he adds a fifth segment and is defeated when an egg hits his head the once more.