Plasmarine

Plasmarine is the boss of the seventh dungeon in Oracle of Ages, Jabu-Jabu's Belly. He looks like a large jellyfish. He only has a few attacks: he can swim into you, create a shield of electricity that will damage you if you touch it with any weapon, or shoot an orb at you that matches his colour. When Plasmarine shoots an orb at you, hit him with your Long Hook. This will cause him to change colour, and he will be hit with the orb of the other colour. He will be damaged by this. About 7 hits with a different-coloured orb will defeat Plasmarine.