Oscar Chang and I encountered this bright yellow spongy mass on a mossy rotten log on the south (left looking downstream) bank of Fox Creek, about 50 m up from the confluence with South Fork, in early June 2013, when we were helping Hiromi Uno install her mayfly-trout experiment. The vivid slime mold color got our attention! Slime molds, considered protists like ameoba even though they are societies rather than single celled organisms, deserve our attention. Some very clever Japanese scientists have made them seek food through mazes, and found out that foraging slime molds could eventually optimize traffic patterns through some major cities of the world—check out slime mold foraging here: http://www.scientificamerican.com/article/brainless-slime-molds.
Oscar and the Fox Creek Slime Mold