Carock

Essentially a large Wizrobe, this boss guards the Maze Island Palace. He can be defeated only by using the Reflect Spell to turn his own magic attacks against him.

Theory
Carock bears an uncanny resemblence to the magician who tricked the Prince and placed Princess Zelda under the spell. The manual says that the magician died after completing the spell. It is possible that the magician and Carock originate from a clan of magicians. However this is only a theory.