Fungus

It stopped raining just now - long enough for me to walk down the garden. When I spotted this lying on the ground, I thought at first it was the brain of some small mammal - a squirrel's maybe, or a baby rabbit's. But, on closer inspection, I found it was simply a fungus. Not sure what kind. It has quite a firm, spongy feel to it. Perhaps a member of the Lycoperdales family? Didn't think they appeared till the autumn, but all this incessant rain could confuse a fungus into thinking it was later in the year; that and the cool air.