Vitreous

Vitreous is the boss of Misery Mire, the sixth dungeon in the Dark World of The Legend of Zelda: A Link to the Past. Vitreous is one huge eyeball surrounded by many smaller eyeballs.

Strategy
To defeat Vitreous, Link must use the Hookshot to grab the mini-eyeballs, and slash them repeatedly with his sword. This process goes faster if he has the Tempered Sword. Vitreous will only attack Link by shooting lightning at him. This can be avoided easily, because Vitreous indicates when it is about to attack by turning green to white.

When this happens, Link should run to the opposite side of the room. Once all the mini-eyeballs are gone, save for the ones that do not attack, Vitreous starts bouncing around the room trying to squish Link. He must continue to slash it with his sword until it is defeated. Link will be rewarded with a Heart Container and the crystal containing the sixth maiden.