Star Trek TOS: Episode 18 - Arena (1967)

Quite possibly the worst fight scene ever choreographed, this duel between Captain Kirk and the Gorn captain is so bad it's good! Despite (or perhaps because of) the crude, almost laughable, action in this episode, the slow-moving but tough Gorn captain has become one of Star Trek's most popular aliens.

The lizard suit was designed by Wah Chang, who also created such memorable Star Trek props as the tricorder, the communicator (which is thought to have inspired modern "flip" phones), and tribbles.