Gremar

Mass Effect & Mass Effect 3
Gremar is an icy terrestrial world with a thin atmosphere of carbon dioxide and krypton. Its surface is mainly composed of frozen ammonia and with deposits of tin and other light metals.

When exposed to sunlight, Gremar's ammonia can melt, forming equatorial seas of the toxic chemical. This has allowed a profusion of simple fungus and lichens to evolve in the low-energy environment. A by-product of their metabolism causes them to glow very faintly. While the light of an individual is insignificant, large patches seem to reinforce the light of one another, and are visible from space.