Coprinopsis lagopus

Coprinopsis lagopus, commonly known as the hare's foot inkcap, harefoot mushroom, or rabbit's foot inky cap, is a species of fungus in the family Psathyrellaceae. It is commonly known as the harefoot mushroom due to the vague resemblance of the young fruit body to the paw of a white rabbit.

It is a delicate and short-lived fungus, the fruit bodies lasting only a few hours before dissolving into a black ink – a process called deliquescence.