Certified GKH Gardening Expert
Not technically, but it is close enough to be considered one. Dog Vomit Slime Molds are very beneficial to the garden, though unsightly.
Their diet consists of bacteria, and when you see them it is likely that you have a bacterial infection in the area. It should be left to clean up your soil, as the bacteria present may harm your plants.
Here is an article that will give you more information: