Hair ice or sometimes called beard ice is an unusual phenomena that only occurs in very set climatic conditions and only with dead wood with a particular fungi in it.
Unlike other forms of frost which we know about and see often, like hoar frost in the pic below
Hair ice only forms at certain temperatures and in certain conditions but the result can be spectacular
From a distance it can look like a plastic bag or other discarded trash
On closer inspection it looks a little like a fungus, but really close up..its pure ice and it's wondrous when it forms like this
You'll never see sights like this for real if you don't get out into the woods..