Kukulkan

From Memory Alpha, the free Star Trek reference.

Kukulkan was an ancient and very long-lived being, the last of his species. Despite his appearance, he was benevolent.

He visited Earth in the distant past, and was instrumental in the technological and architectural advances of the Egyptian, Mayan and Aztec civilizations. He also taught them new art and agriculture techniques. He hoped that they would combine this knowledge to complete Kukulkan's city and live in peace. They did not. Kukulkan's visit to Earth is manifested in history by legends of a winged serpent creature that came from the sky bringing knowledge. These records were available in the library computer.

He has also been identified with the lore of Quetzalcoatl and the legend of the Chinese dragon. (TAS: "How Sharper Than a Serpent's Tooth")

Kukulkan was voiced by James Doohan. In the German version of the episode, Kukulkan was spelled "Kulkulkan." Kirk/Shatner almost constantly pronounced the name "Kuklukan."