Bulb Yoshi

Bulb Yoshi is one of Yoshi's various power-ups in the game, Super Mario Galaxy 2. Yoshi becomes Bulb Yoshi whenever he eats a Bulb Berry. When that happens, he'll turn yellow, and begin to glow.

In this state, Yoshi can reveal passages that aren't normally seen. However, the effects of this power-up are only temporary, so he must eat another nearby Bulb Berry to prolong it.