Here are images of hair that came out in the shower. You know, the “scare hair” that balls up and just isn’t right. After sealing it in clear packing tape it ended up forgotten in a drawer. In a few months it “cultured” and formed what I believe is a Hartig Net.

Wikipedia Definition:
Hartig net is a hyphal network, that extends into the root, penetrating between epidermal and cortical cells. This network is a site of nutrient exchange between the fungus and the hostplant.[1] Hartig net is typical for ectomycorrhiza. The early research on the anatomy of the interface between ectomycorrhizal fungi and plants was done by Robert Hartig, a 19th-century German plant pathologist, so the Hartig net is named after him.

For reference some internet images for a Hartig net:









Now my images...
"Y" forming from a hair:



Net draped around hair:


Different branching formations:



Some are almost phantom like:




Formed around a hair shaft/root:










Since I’m no expert I can only guess which kind of fungus this could be. I have a theory, but that's another post...
Here's a long but thought provoking read on beneficial and pathogenic roles fungus can play:
http://www.apsnet.org/edcenter/intropp/PathogenGroups/Pages/IntroFungi.aspx