Even if the cap fits, don't eat it...

Shaggy Ink Cap. The shaggy mane is so large and distinctive that it is probably one of the easiest mushrooms to identify. It is a good one for beginners are there is no chance of mixing it up with lots of other types of mushroom.

The cap of a fresh specimen is a long, white cylinder with shaggy, upturned, brownish scales. The gills are whitish, and the entire mushroom is very fragile and crumbles easily. The older it gets, the more mature the shaggy part gets and start to gradually dissolve into a black, inky fluid, leaving only the standing stalk. Size 4" to 6" tall, sometimes larger.

As far as I'm concerned all wild mushroom looking type things will kill you if you put them in your mouth. I put my longevity down to this wuss philosophy.