Syzygospora mycetophila on Gymnopus dryophilus

The Collybia Jelly is parasitizing a group of Oak-loving Gymnopus mushrooms and has distorted them beyond recognition. Two orange Oak-loving Gymnopus are seen at the left.

From mushroomexpert.com:

Apparently Syzygospora mycetophila is not, strictly speaking, the stuff that we see on the mushroom; the jelly-like growths are composed of tissue from the mushroom itself and are induced by the parasite, which uses them for its own ends.