This is a Lichen called “Fairy Puke” … specifically Icmadophila ericetorus. The photo was taken near a research study plot in Jedediah Smith Redwoods State Park. It is not rare, but far from common-place. I see Black Bear about as often as Fairy Puke in Redwood National and State Parks. Although, I’d probably find Icmadophila more often if I kept a sharp eye out for it. The green / blue and faded pink spots across the surface  of the decayed log are all part of the lichen.

Fairy Puke Icmadophila

This is one of the lichens that author Richard Preston wrote about in his best selling book The Wild Trees