Birch Fungus

I often come across fallen birches and their associated polypores when I'm out paddling. Fomitopsis betulina bursts from the bark of a weakened tree that's been compromised through stresses (drought being one of them). The infection possibly gets in through wounds and broken branches, and then lies in wait until the time is ripe for its activation, breaking down the wood.

 

It looks like a large hoof has formed on the tree. Many insects feed on and breed in the fruit body.

According to Wikipedia, this is the fungus that "was carried by "Ötzi the Iceman" – the 5,300 year old mummy found in Tyrol, with speculation that the fungus may have been used as a laxative to expel whipworm."