Coprinus comatus

About

Coprinus comatus, commonly known as the shaggy ink cap, lawyer's wig, or shaggy mane, is a species of fungus. The young fruit bodies first appear as white cylinders emerging from the ground, then the bell-shaped caps open out. The white caps are covered with scales, the origin of its common names. The gills beneath the cap are white, then pink, then turn black. This mushroom is unusual because it will turn black and dissolve itself in a matter of hours after being picked or depositing spores.

Summary from Wikipedia