The Zeltok were a blue-skinned humanoid species native to the planet Zeltok. They became extinct when the planet self-destructed in 1465.
History and specifics[]
The Zeltok were an advanced civilization which built cities and developed art. In the 15th century, the Zeltok were wiped out by invading armies of Zeltok ants. At least one person survived the assault, however, and maintained a meager living in a fortress built by Zeltok gorillas until the planet blew up. (TOS comic: "Vibrations in Time")