The Ruby Moon of Doom was the moon of an unknown planet. In 3000 it was commandeered by that planet's inhabitants to visit Earth periodically, where it abducted Earthlings with its own gravity so they could be transformed into robots to dig out the giant battle robot, Kolossus, who had been entombed in the rock for a million years. Kolossus would then invade Earth and take it over for them.
However, Pedrobot, the robotic form of Pedro the Mailburro, defeated Kolossus and forced the aliens to leave, abandoning the moon in Earth's orbit. This made things very pretty at night and led to Earth being nicknamed "The Planet of Rose and Silver". Of course it also wreaked havoc with established tidal forces and stuff, but let's focus on the positives.