Dog vomit slime mold (Fuligo septica) is a common problem this time of year. After gardeners put down a fresh layer of mulch they often see this aptly named growth showing up a few weeks later. This dog vomit is actually a slime mold that exists as an almost clear thin blob that crawls around the surface of the garden - this is its plasmodium stage. When it is developed enough to reproduce, it pulls itself together into the more recognizable pile that some describe as scrambled eggs. Eventually the scrambled eggs will brown to the recognizable pile of canine emesis. At this point, the slime mold spores are released to start the process over again.
Dog vomit slime mold is not harmful to plants. There is no way to totally eradicate it from the garden. However, some people have reported that watering in new mulch does help reduce the amount of slime mold. Also, any pile of sporulating slime mold can be scooped up with a shovel and deposited out of sight - breaking it up or blasting it with water will only help it spread its spores.