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 travel through bodies of water, which normal Yoshis cannot travel through because they 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 harder to reach the Yoshi Block before the transformation's time runs out and the Yoshi is sent back to the place where they touched the Morph Bubble.

The Yoshi Submarine reappears in Yoshi's Island DS. However, it is no longer able to launch torpedoes.

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 look more like regular torpedoes.
 * Despite the Yoshi Submarine's artwork shown above being brown, Brown Yoshi never gets the opportunity to morph into a submarine.