I was today years old when I learned that hair ice only forms in the presence of a specific fungus; and that even though that had been the theory for about a hundred years, scientists didn't even identify which one until 2015. https://en.m.wikipedia.org/wiki/Hair_ice
@eldang It's a whole confluence of particular conditions, which makes it kind of magic. Especially that the fungus has some sort of function that keeps ice from recrystallizing, and nobody understands it yet? So cool.
@erinbee !!! I did not know that. I thought it just needed exactly the right temperature and humidity. This is much cooler.