Black Comet

The Black Comet was the main spacecraft of and home to the Black Arms. It traveled along an extended orbit around the Sun that put it in contact with various planets through the galaxy, passing the Earth once every 50 years, until it was destroyed in a flyby of Earth in the early 21st century.

Mid-20th century
The Black Arms made contact with Gerald Robotnik on the Space Colony ARK when the Black Comet passed Earth in the mid-20th century. Their leader Black Doom helped Robotnik decipher his research on the Echidnas and offered help in developing the Shadow Project.

Early 21st century
When the Black Comet returned to Earth 50 years later, it was with Black Doom's intent of using the now-complete Shadow the Hedgehog to initiate the Black Arms prosperity ritual. Shadow stopped the Arms, however, and the Comet was destroyed.