Physarum Polycephalum
A bright yellow slimy blob is commonly seen in the summer on mulched flower beds. It is not pretty, unless you like yellow, and it soon gets uglier. The yellow blob turns gray, becomes hard, then breaks down into a brown powder. People complain that the yellow blob looks like dog vomit and that the brown powder stains sidewalks.
The brown powder is made up of the millions of spores it makes in order to reproduce. Other slime molds are tiny and difficult to find. Their spore-producing structures are not an ugly crust like Physarum, but rather beautiful colored spheres or Popsicle shapes.
For treatment, symptoms, and more information see www.mold-survivor.com