The Gorn (real name not revealed) is the captain of a starship from the alien empire known as the Gorn Hegemony and appeared as Captain Kirk's opponent in the Star Trek episode "Arena". A reptilian alien of great physical strength, but also intelligent no less than a human; the Gorn cannot be considered much of a villain, actually; since he and Kirk were forced into the duel to the death by a godlike alien figure. Nevertheless, thanks to his iconic appearance and the fact that some of the fight sequences in this episode have been deemed some of the worst coordinated in all television history by some fans; the Gorn has become one of the most popular and fondly remembered Star Trek aliens.
Conflict initiated between the United Federation of Planets and the Gorn Hegemony after the Gorn's successfully taking control over a Federation outpost, which the Gorn declared to be within their territory. During space combat between the Gorn's ship and the USS Enterprise a sophisticated and powerful alien race named the Metrons appeared unexpectedly and took both ships into custody by disabling their power. The Metrons claimed such warlike behavior to be primitive and chaotic and forced the captains of the respective ships to resolve their differences personally, in a hand-to-hand combat on a nearby desert planet. The winner would be allowed o leave, while the loser would have his ship destroyed. Kirk and the Gorn were transported to the planet by the Metrons and engaged in battle, employing a variety of techniques. While the Gorn is stronger, he is also slower due to his reptile metabolism; but his intelligence is not below human. Eventually, Kirk manages to build a primitive cannon using the materials available and hits the Gorn, becoming in advantage; but refuses to kill him. The Metrons acknowledge this as a noble attitude and decide to return both captains to their respective ships unharmed.
After this, the Gorn species would have only cameo appearances in the animated series and in an Enterprise episode set in the mirror universe. They would play a major role in the non-canon graphic novel The Gorn Crisis set during the Next Generation era.