Xylaria polymorpha, commonly known as dead man's fingers.
https://diqn32j8nouaz.cloudfront.net...m_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...675#post178431
https://www.homemadetools.net/forum/...853#post137188
https://www.homemadetools.net/forum/...506#post162362
https://www.homemadetools.net/forum/...040#post134111
