Omphalotus nidiformis, or ghost fungus, is a gilled basidiomycetes mushroom most notable for its bioluminescent (ability for producing light) properties. Its bioluminescence, a blue-green color, is only observable in low light conditions when the eyes get dark-adapted. Not the entire fruit body glows, only the gills do, a phenomenon also called "foxfire". This is due to an enzyme called luciferase, acting upon a compound called luciferin, leading to the emission of light much as fireflies do. Its fruit bodies are generally found growing in overlapping clusters on a wide variety of dead or dying trees. It could be mistaken as an edible pleurotus, but like most glowing mushrooms, the Omphalotus nidiformis is deadly poisonous!