A striking mushroom. up to almost a foot tall. Cap long cylindrical, whitish, with shaggy scales. Stalk thick, light brownish. As mushroom matures cap turns dark and then liquefies into a black inky liquid that can actually be used as ink. It lives on decaying matter and commonly pops up in lawns and on roadsides in the fall.
Common throughout much of North America, but only appearing for a few days when conditions are right. In Wildwood can be very common along the bikeway at the right time in autumn.
Unmistakeable, based on its size, shagginess and bizarre habit of liquefying. Alcohol inky (Coprinopsis atramentaria) also turns black and dissolves, but this is a much smaller mushroom with a much different shape. Surprisingly they are only distantly related.
The process of liquefaction is shown in the bottom row of images; note particularly the inky liquid flowing down the stalk in the last photograph. The reason for this liquefaction is not known with certainty, but the spores mature from the bottom up and the cap similarly liquefies from the bottom up, so that the mature spores are always just at the edge, ready to be released and caught by the wind. Liquefying would also return any nutrients used to make the cap to the soil to be reused by the mushroom before any animals can eat them and run off.