Imagine that you are lying in bed and an amorphous mass of protoplasm (cell contents) engulfed and digested you. Well if you were a microorganism or organic matter, this is what a slime mould would do.
A definition is "A simple organism that consists of an acellular mass of creeping jelly-like protoplasm containing nuclei, or a mass of amoeboid cells. When it reaches a certain size it forms a large number of spore cases."
Slime moulds are amazing organisms where individuals can join together and coordinate like they have a brain. When the protoplasm is on the move one can see the contents streaming backwards and forwards under a microscope. They are not fungi but somewhere between them and protozoa. They occur in lawns; white ones and who could forget the yellow ‘dog vomit’ slime mould.
Below is a strawberry slime mould Tubifera ferrugininosa that I found in a huge dead marri trunk. The white material has come together to form the red fruiting mass that forms globular spore containers. As they mature the mass becomes brown, sheds spores and fades.
See below that an amalgamated slide show of progression of a white slime mould from clear protoplasm to spore balls