Great images of this 'ink cap' fungus in its various stages of development. This common name has come from the 'dripping black liquid' you noted. The black is mature spores. As these spores mature the cap liquifies (deliquescence) from the outside edge towards to top of the cap and finally all that is left is the stalk (stipe) with its ring (annulus) and a remnant of the cap. These are saprotrophs that is they are decomposers that recycle essential nutrients from the decomposing organic matter back into the soil for plants