Tan or brown
A group of silicon-based sentient invertebrates, related to mynocks, evolved on a lone asteroid in the MZX32905 system near Bimmiel. The creatures referred to their asteroid, which had been imbued with the dark side of the Force, as "the Home." They had triangular yellow eyes and some had hands on their wings.
The creatures subsisted off stellar radiation and silicate materials. It is believed that the lingering dark side energies were what allowed these creatures to evolve. Presumably, it was for this reason that the creatures could not reproduce anywhere else in the galaxy than the Home, an act which they referred to as "the Return."
These creatures developed a fairly advanced culture, complete with social hierarchies. They used a form of keeping records using information imbued sculpture and tassels.
At one point in their society's history, the ruling class withdrew themselves into the asteroid's caverns, effectively cutting themselves off from the stellar radiation they needed to survive. They eventually became exiles in their own caves, starving to death, barely surviving on the mineral veins.
At some point, however, one of them learned to detect and tap into the dark side energy already present there. This individual rose to become leader of the exiles. Using their new found powers, this one led them to break free from their self-imposed exile and conquer the other creatures living on the asteroid's exterior.
The new dark side regime was capable of many powerful force abilities which were related to their mynock nature. They were capable of leeching energy from living beings over great distances, even their own kind. They were also capable of instantaneous communication over great distances, something even most skilled Jedi were incapable of.
At some point, the species went extinct. It is unknown what caused the sudden demise of the entire species. However, due to the fact that they could not reproduce outside of their asteroid, a fatal contagion or seismic cataclysm on "the Home" could have easily wipe out the whole race quickly. Their dark side echoes would live on for millennia, however, and were eventually discovered by the Sith Lord Darth Vectivus.