Guardians of the Stars
Alien Contact 1
The only possible sighting of an alien craft on record is one picture found in the data of a star system being surveyed. The object was picked up on sensors as a asteroid or other mostly metallic body drifting in space. The sensors only realized something was amiss just before the ship left the system as the object was not at the expected location and had in fact disappeared. Optical telescopes had passed over the object while it was drifting and so we have quite clear pictures of what looks like a cruiser or possibly battleship sized space craft.
It has a style fairly reminiscent of conventional human styling, which has lead some to speculate it was a human built ship from a fringe group. However no such group is known to possess the facilities to produce anything on this scale or to have purchased such from somewhere within the known human run systems. Other believe it was made up using advanced graphics technology and faked sensor logs.