This is the slime mould (myxomycete) Fuligo septica var. flava, that we found on a rotting log at Smardale Gill National Nature Reserve near Kirkby Stephen in Cumbria on Tuesday. These are amazing organisms, that start life as microscopic amoebae that germinate from spores, slither over wet surfaces and ingest bacteria in their path. Ultimately they aggregate to form the slug-like slime mould, that continues to crawl and grow until it's mature - this one has just reached maturity and looks like miniature scrambled egg. What happens next is that it begins to lose water and produce spores that will blow away in the wind and germinate into new wandering amoebae, feeding and on the lookout for other amoebae that they can aggregate with.
This is the same organism, photographed about two hours later and if you double-click to enlarge the images you can see that its structure is already changing, from miniature scrambled egg to miniature yellow Brillo pad .... and soon it'll dry out and release its spores.