Growing on the bark of an oak. Looks nasty.
No identification made yet.
No interactions present.
was the tree actually alive? If tree still healthy then perhaps a huge slime mould but perhaps more likely one of the many fungi attacking tree. if it is a fungus then need more detail (and probably microscopic examination as I suspect there are lots that look like this).
I'm fairly sure that the tree was alive, although its canopy was way up high in the wood and I confess that I did not check.
A slime mould is an interesting suggestion.
University of Edinburgh and Biodiversity Observatory (OU)
Lat/Lng: 51.585166666667, -0.1505
OS grid ref: TQ282889