It's likely a inky cap. They get gross and black drippy when they age. Edible when young, but never to be eaten with alcohol as they are then toxic. Best to avoid.
Yup, aka Shaggy Manes! Definitely edible, but they really do start to disintegrate into that inky black grossness soon after picking. Luckily they pop up in my yard all the time, so if I happen to notice they'll find their way into whatever I'm frying up. One of the few wild mushrooms I'm comfortable with eating since it's so distinct.