Beware the Boo Brigade
From the Super Mario Wiki
Yoshi starts the level in a fort with an Egg Block and some enemies nearby. Entering a nearby pink door causes Yoshi to appear in an area with blue smiley face blocks which rotate in a set direction. Eventually, Yoshi reaches an area with an Arrow Lift that can be used to transport him to the Middle Ring.
After another Arrow Lift ride, Yoshi reaches the boss door. Inside waits Kamek, who must be hit by the ceiling three times in order for Yoshi to defeat him and clear the level.