This weekend I went up Rattlesnake Mountain, near North Bend, Wash., and had a delightful hike through the woods. We saw a couple dozen of these:
This is a slime mold: Fuligo septica, or if you prefer the common name, dog vomit slime mold.
What we're seeing is the mobile, amoeboid form of the slime mold, one giant oozing, branching, decaying wood devouring cell. At the right stage, and on a diet of wood chips or beauty bark, it can look so much like dog vomit that it triggers calls to the veterinarian.
Here's one that is a little further along in development:
There's a black, bruise-like blur in one spot where spores are forming. Eventually, it'll go through a series of changes, ending up as a blue-black sporing body.
Also coming into bloom on the forest floor was Indian Pipe. Indian pipe is ghostly white and fungus-like because it doesn't get its energy from sunlight. Instead, it uses a fungus as an intermediary to get energy from nearby trees.