Moldorm is the boss of Tail Cave. It's a large worm-like creature that moves quickly around the arena. Its only attack is to try and knock Link off the platform. To defeat Moldorm, you need to hit its tail with your Sword. After each hit, it will speed up. Use Roc's Feather to jump over its body and avoid being knocked off. If you fall, you'll have to climb back up and restart the fight. Focus on quick strikes to its tail and evasive jumps.
While this encounter emphasizes verticality and timing, the rhythmic sword strikes required to hit the boss's tail evoke the precise combat mechanics found in Zelda II: The Adventure of Link.