Submarine Yoshi

The Yoshi Submarine is a form that the Yoshis can transform into in Super Mario World 2: Yoshi's Island by touching a Morph Bubble containing its picture.

The Yoshi Submarine form can be used to dive through bodies of water, since normal Yoshis are unable to dive, and fire homing torpedoes at enemies. Getting hit in this form causes the player to briefly lose control of the Yoshi Submarine, making it more difficult to reach the Yoshi Block before the transformation's time runs out.

The Yoshi Submarine reappears in Yoshi's Island DS. It is no longer able to launch torpedoes, however. In Yoshi's New Island, the Yoshi must enter a Whirly Gate with its picture to become Yoshi Submarine. It works similarly to the original, except that the player must tilt the system to steer it.

Trivia

 * Although the torpedoes the Brown Yoshi launches in the Yoshi Submarine's official artwork resemble Yoshi faces with a propeller on the back, the torpedoes seen in the game resemble regular torpedoes.
 * Despite the Yoshi Submarine's artwork shown above being brown, Brown Yoshi never gets the opportunity to morph into a submarine.