Wolf's milk slime.
(Lycogala epidendrum,)
Wolf's milk slime is a slime mould with a small (diameter to 1.5 cm) ball- or cushion-shaped fruiting body. It varies greatly in colour depending on age, from the greyish-pink colour of the immature specimens seen above to yellowish-brown or greenish-black. The cushion has a rough to warty texture, and releases a pinkish-grey paste-like flesh when popped. This flesh, which contains spores, turns powdery and ochre brown in colour with time. Original public domain image from Flickr