http://en.wikipedia.org/wiki/Great_Race_of_Yith"snip...The Great Race ... waxed well-nigh omniscient, and turned to the task of setting up exchanges with the minds of other planets, and of exploring their pasts and futures. It sought likewise to fathom the past years and origin of that black, aeon-dead orb in far space whence its own mental heritage had come – for the mind of the Great Race was older than its bodily form. . . The beings of a dying elder world, wise with the ultimate secrets, had looked ahead for a new world and species wherein they might have long life; and had sent their minds en masse into that future race best adapted to house them – the cone-shaped beings that peopled our earth a billion years ago.
—H. P. Lovecraft, "The Shadow Out of Time"
One of the Great Race, under green lighting, as seen in the Call of Cthulhu: Dark Corners of the Earth video gameThe Great Race are beings of enormous intellectual and psychic powers that once dwelt on the dying world of Yith. They escaped the destruction of their home planet by transferring their minds to the bodies of a species native to the Earth in the far distant past. They lived on this planet for 200 million years or so, in fierce competition with the flying polyps, until this enemy finally destroyed their civilization near the close of the Cretaceous era (about 65 million years ago).
In the bodies they inhabited on the Earth, they were tall and cone-shaped, rising to a point with four strange appendages – two terminating in claws, a third in a "trumpet", and the fourth, a yellow globe which functioned as a sensory organ. They have no genders and reproduce by spores instead. The unique ability of this scientifically-advanced race was to travel through time by swapping minds with creatures of another era...snip"