The photograph shows three small, mature fruiting bodies (aethalia) of the slime mould species Lycogala epidendrum; they were growing on the dead tree that can be seen to the right of the path in
NS3984 : Path through the woods.
For younger specimens, which are more colourful, see
NS3977 : A slime mould - Lycogala epidendrum.
They are individually less than a centimetre across; the one at the bottom of the image has a hole underneath, through which some of the dark-grey spore mass has already emerged. [The colour of the spores helped in distinguishing this species from the similar L. terrestre (see below), as did a closer examination of the scales on the surface of the fruiting bodies.]
Compare
NS3984 : A slime mould - Lycogala terrestre (plasmodium), photographed nearby. [Some other Lycogala species occur in Britain and Ireland, but L. epidendrum and L. terrestre are among the most commonly observed of slime moulds. See also
NS3781 : A slime mould - Lycogala terrestre.]