S1·E36 The Great Chieftain Cyclops

The 999 stops at an abandoned artificial colony world. Tetsuro is pleased with its appearance but Maetel is puzzled that the colony looks quite different than it did on her last visit. They investigate further, and are set upon by a terrified mob of physically identical men. Maetel recognizes their face as being that of the colony's architect, Dr. Cyclops.