This appeared to be a slime mold. It was white, and had made some sort of fruiting body, which seemed to have dried out by the time I found it. Some dry membranes are also visible around the fruiting bodies.
These slime molds were growing in a ponderosa pine forest. Their appearance is likely due to recent rain. The two separate fruiting bodies shown were nearby and probably had the same origin.
The slime mold was on dead pine needles, and seems to have spread along them. Perhaps it was feeding off them.