Found this today whilst out and about, the jury seems to be out on it’s edibility so I think I’ll give it a pass on trying it.
Wiki says: Exidia glandulosa (common names black witches' butter, black jelly roll, or warty jelly fungus) is a jelly fungus in the family Auriculariaceae. It is a common, wood-rotting species in Europe, typically growing on dead attached branches of oak. The fruit bodies are up to 3 cm (1.2 in) wide, shiny, black and blister-like, and grow singly or in clusters. Its occurrence elsewhere is uncertain because of confusion with the related species, Exidia nigricans……. http://en.wikipedia.org/wiki/Exidia_glandulosa