I suspect most folks will have, at some stage, encountered the organism pictured below.
It’s a slime mould.
These images are possibly the same species, which I suspect is Fuligo septica, a slime mould that goes by the unfortunate common name of Dog Vomit Slime Mould.
Slime moulds are remarkable organisms. They were once thought to belong to the fungi kingdom but are now classified in the kingdom Protista – they live their lives as single cells that mass together into large reproductive structures when food is in short supply. I found these two specimens about a week ago, the first on a layer of decomposing wood dust, the second on soil in a garden bed.