Precursor (Star Control)

The Precursors are a vanished, ancient, technologically advanced race from the Star Control games. They are known to have ruled the galaxy for several thousands of years and then vanished without a clue, presumed to have either gone "somewhere" or become extinct. They didn't clean up after themselves and their various, hyper-advanced artifacts (including the Ultron and the Sa-Matra) have been pivotal in the fates of the younger races. Precursor devices have been discovered on various planets in the region of space accessible to the player, but only a single complete, intact installation has been found, the one which begets the beginning of the story of Star Control II, becoming activated by a group of Earthling scientists and assuming its role of creating a Precursor starship on the planet Unzervalt (also known as Vela II).

Physiology
The Precursors are only known to have been big, shaggy creatures, known to the Slylandro as the Shaggy Ones. (This is very likely influenced by the film Forbidden Planet, in which a superior alien race's size can be guessed only from the size of their doorways.)

History
In Star Control II, it is implied that the Precursors had assembled a series of sensor-defying "Rainbow Worlds" and used them to point the direction in which they had left.

In Star Control 3 it is revealed that to protect themselves from the Eternal Ones, a race that inefficiently consumes the energy of all sentient beings once an eon (the feeding), the Precursors genetically modified themselves to mentally resemble the intelligence of a cow. They created mindless robots (the Daktaklakpak) to reverse the process after the Eternal Ones left. They also left huge caches of their technologies on planets in hopes other races could find how to defeat the Eternal Ones. During the last feeding, their robots malfunctioned, leaving them stranded at that intelligence level for thousands of years. Humans, forever searching for the Precursors but oblivious to their plight, along with many other races found the meat of the Precursors, called by them Ortogs (a 6 legged cow), more delicious than cow, and hence raised, domesticated, and consumed them in massive quantities. In the game the process is temporarily reversed on a single Precursor, giving this knowledge to the player.