Master Stalfos

The Master Stalfos is a mini-boss in Link's Awakening appearing in the fifth dungeon, Catfish's Maw. He is a big Stalfos Knight who steals the Hookshot from a chest in the dungeon, leaving a note for Link to find. He flees from Link after sustaining a certain amount of damage in battle. Master Stalfos is fought four times in four different rooms in the dungeon each with a skull pattern on the floor. Each room is numbered with a block in the corner of the room, and he will flee from the first room to the second, then from the second to third, before finally hiding in the fourth room deep in the dungeon. Like a Stalfos Knight from A Link to the Past he will crumble after hit by the sword before reanimating. While crumbled, he must be hit with a Bomb to damage him otherwise he will simply keep fighting. Unlike Stalfos Knights, he actively swings his sword at Link and is able to send him flying, and defends himself with a large shield. Upon his final defeat in the fourth room, he drops the Hookshot.

Trivia

 * It is possible to destroy Master Stalfos in the first three battles by using two Bombs on him during the final hit before he flees. This is easiest done by using Bomb Arrows. When destroyed, he will drop a Small Key. He will still return later in each subsequent room, allowing Link to collect three extra Small Keys.