Wildlife Spotting

A red-brown lichen? Or some sort of fungus or liverwort? I have no idea. I found it under an oak tree right after a heavy rain, so I assume it fell from the tree. The underside (last picture) had a sort of hole in the middle that I thought might be the attachment point for where it had been stuck to the tree. It was still damp from the rain and felt rubbery.

Could it be black witches' fungus?