The reptilian Gorn commander who destroys the Cestus III outpost and is forced by the Metrons to fight Kirk in single combat.
The Gorn Captain commands the ship that attacks the Federation outpost on Cestus III at the start of Arena. Kirk pursues the vessel into unexplored space, where the Metrons halt both ships and transport the two captains to a rocky planet, telling them to fight to the death so that the loser's ship can be destroyed.
The Gorn is far stronger than Kirk but slow, and the two battle across the desert with rocks and makeshift traps. The Gorn explains that his people regarded the outpost as an invasion of their territory. When Kirk improvises a crude cannon and wins, he refuses to kill his opponent, and the Metrons spare both ships in recognition of that mercy.