- Ensemble Dark Horse: The Gorn. Appearing in only this episode, and hardly ever getting a mention again, they still captured the imaginations of many Star Trek fans. Probably due to the combination of an intimidating and cool design (carried off as well as budget '60s special effects could) and one of the first genuinely morally grey conflicts. In the EU, the Gorn have run the gammut from joining the Federation to allying with the Klingons to being a galactic power in their own right.
- Fight Scene Failure:
- It Was His Sled: The first half of the episode is a tense encounter and pursuit with the mysterious ship that attacked a Federation outpost against enemies the crew never see, which is rather undermined by the fight with the Gorn captain being one of the most famous scenes in television.
YMMV / Star Trek S1 E18 "Arena"