Aqua Lakitu

Aqua Lakitus are a water-dwelling equivalent to the Wall Lakitus that appear in Super Mario World 2: Yoshi's Island. They are only found in Naval Piranha's Castle.

Aqua Lakitus hide underwater and throw Spiny Eggs at Yoshi. When underwater, their snorkel gear can be seen just above the surface, and they are immune to most forms of attack. Yoshi can defeat an Aqua Lakitu by eating it, stomping it, or throwing an egg at it when it is surfaced.

Super Mario World 2: Yoshi's Island

 *  Official Nintendo Player's Guide: In terms of sewer vermin, these bomb-throwers rival New York City's famous alligators.