Gomess is a Mini-Boss that resides in Stone Tower Temple in Majora's Mask. He surrounds himself with bats as a defense. If Link stands far away from him, he'll send his bats after him to attack from all sides.
Gomess has two attacks, one is to charge towards Link, which can easily be deflected with his shield. The other attack is to swipe at him, which can be reached over Link's shield at the right distance. It will miss if Link is right up against him, or just out of range. Furthermore, Link has to stay at mid-range, close enough so that he doesn't send his minions after him. Link has to shoot him with his Light Arrows to get the bats to fly away for a short time. During the time, he is vulnerable in his heart, (the orb in his chest). Link gets close and slashes him with his sword. Link has to do this eight times and then this rival will be defeated.