Spacecube of Doom is an episode of the Space Ghost segment of Space Stars. It first aired 14 November 1981 on NBC.
Summary[]
After helping The Herculoids free a mammoth from a tar pit, Space Ghost discovers that a space cube is stealing all the precious metals in the universe. When the Phantom Cruiser is also stolen, Space Ghost discover that the robot Cubus is wanting to save the logical universe with his super computer Ultima and brainwash the creatures of the universe to think logically.