Melting Toadstools

Out on a dog walk through the woods when these Fungi caught my eye. At first I thought that someone had poured something over them but on closer inspection it appeared to be natural decay.

Regretted dropping my rucksack onto the floor as I took the photograph as when I picked it up I realised it had picked up some of the inky deposits. Fortunately they easily washed off.

Has anyone come across this phenomenon before?