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, and can even brighten up dark places. However, the effects of this power-up are only temporary, so he must eat another nearby Bulb Berry to prolong it.