Lactarius indigo

Lactarius indigo is a fungus. It is commonly known as the indigo milk cap or the blue milk mushroom. It is very common. and grows naturally in eastern North America, East Asia, and Central America. It has also been found in southern France. 
"L. indigo" grows on the ground in both deciduous and coniferous forests, where it forms mycorrhizal associations with many different trees. The fruit body color ranges from dark blue in fresh specimens to pale blue-gray in older ones. The milk, or latex, that oozes when the mushroom tissue is cut or broken is also indigo blue, but slowly turns green when it is exposed to air. 
It is an edible mushroom, and is sold in markets in China, Guatemala, and Mexico. In Honduras the mushroom is called a chora, and it's generally eaten with egg; generally as a side dish for a bigger meal.