A giant feathered serpent, Kukulkan, claims the Enterprise crew as his worshippers.
The Enterprise encounters a being that appears as a giant feathered serpent and who claims to be Kukulkan, the god of the Mayan and Aztec peoples. He demands the worship of the crew, and Kirk must stand up to him and prove that humanity no longer needs gods.
The story echoes Who Mourns for Adonais?, and suggests that ancient myths were inspired by visitors. It features a large, colourful creature, which was easily depicted in animation. Fans remember Kirk's argument and the story's idea that the legends of Earth may have a cosmic origin.