Fire Power (Yoshi)
From the Super Mario Wiki, the Mario encyclopedia
Fire Power is Yoshi's Power Flower power-up in Super Mario 64 DS. Getting a Power Flower or eating fire will allow Yoshi to breathe fire, though only the former lets him do so as much as he wants for a brief time.
The power-up itself has the most use in ice courses such as Cool, Cool Mountain and Snowman's Land, due to its ability to melt Ice. It can also defeat any enemy on contact, making it very useful when there are enemies in Yoshi's way.