Submarine Yoshi

The 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 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 Submarine, making it more difficult to reach the Yoshi Block before the transformation's time runs out.

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