What is this thing? My assumption is that a bug made it.
CLOSED: 1 inch hollow container on side of tree in the NC piedmont
This looks like an old cocoon of a southern flannel moth (Megalopyge opercularis) - see http://www.austinbug.com/survey/2010/pics/4-1-10flannel.jpg
Detailed info on this species can be seen at http://entnemdept.ufl.edu/Creatures/MISC/MOTHS/puss.htm