Wasp Gall or Oak Apple

This interesting thing is actually the home of a wasp larva, where it is protected from the elements while it grows large enough to eat through the shell and emerge as an adult. If you would like to know more about these odd, yet interesting things, here's a Wiki page: en.wikipedia.org/wiki/Gall_wasp

Here's another source of information: www.fcps.edu/islandcreekes/ecology/oak_apple_gall_wasp.htm

This image was taken in December, 2011.