The alien race Captain Kirk fights in “Arena” is the Gorn. The episode introduces the Gorn as a reptilian extraterrestrial species and one of Star Trek’s most recognizable alien civilizations.
First broadcast on January 19, 1967, “Arena” begins after a Gorn vessel attacks the Federation outpost at Cestus III. Kirk pursues it, but both ships are stopped by the Metrons, powerful beings who force Kirk and the Gorn captain to fight on a barren planet.
The Gorn captain is never given an individual name in the original episode. That detail sometimes causes confusion: “Gorn” identifies the species, while “Gorn Hegemony” refers to their government or political power. Kirk ultimately defeats his opponent through ingenuity, then spares his life, convincing the Metrons that humanity is capable of compassion.
The episode’s distinctive costume and deliberately slow fight made the Gorn famous. The species later returned in Star Trek: Enterprise and became recurring antagonists in Star Trek: Strange New Worlds.