It's funny....I know for a fact this is all BS. But a little tiny sliver of my mind wonders...."what if?"
Oh, and regarding the Colonists from the X-Files:
The aliens were forced to abandon the planet during the last ice age as their viral lifeforce is deactivated by extreme cold. Upon their departure, they left behind underground deposits of the black oil virus, in preparation for their return. The virus apparently contains the aliens' genetic blueprints, awaiting reconstitution until the master species returns to Earth. Whilst away from Earth, the Colonists evidently sought out life throughout the universe in an effort to subdue other species and take over the universe. Purportedly, the Colonists planned on returning to Earth in the year 2012, as The Smoking Man later remarks to Fox Mulder that the ancient Mayans were so terrified that they stopped their calendar on the exact date of colonization: December 22, 2012.