Fungi foraging

Even though I'm too wussy to ever eat any fungi I find, I still love going out in autumn looking for them. I think it's their weird shapes and strange habits that I like, seeing something growing straight out of a decaying tree or a bright spot amongst the leaf litter or yellowing grass, just makes a drizzly autumn day a bit less dreary. I have no idea what this white one is - puts me in mind of a sea slug though.