I picked this twig up recently on a walk with a friend. It is so completely covered in lichen that it almost looks like a large hairy caterpillar.  The twig itself is only apparent at either end, like a skeleton providing a structure for the lichen, with just an arm or leg peeking out.

Lichens are said to be indicators of clean unpolluted air. 

I think this one might be Oak Moss lichen, in which case it has long been used in the perfume industry.