Loch Nestor

Loch Nestor is a puffer fish enemy encountered in Super Mario World 2: Yoshi's Island and Yoshi's Island: Super Mario Advance 3. It's the underwater counterpart of Boo Balloon, but the differents is that Boo Balloon chases you, even when you don't throw eggs, and Loch Nestor can't attack you unless the enemy is attacked by an torpedo. It only appears in stages where Yoshi must morph into a submarine. If it is hit by a torpedo, it simply grows two times larger and chases Yoshi. After it is hit three times, it explodes.

Loch Nestors reappear in Yoshi's New Island.

Trivia

 * Loch Nestor derives its name from Nestor, a given name, and the Scottish lake Loch Ness, which is the home of the famous and mysterious Loch Ness Monster (also known as Plesiosaurus and Nessie).