Found by garden club students at an elementary school. The instructor said it was found on a leaf bag and she was fairly certain it was hanging out in its nest (what looked like a white cocoon) until the students started moving the bag. It's about the size of a fingernail, and contrary to what the children first thought, is not a tarantula. To me it looks similar to some images of Phidippus audax that I've come across, but the patterning on the abdomen is different. Perhaps this depends on life stage or gender? If you know who this is, please comment! Would be great to let the kids know who it is (and perhaps an interesting tidbit to further their fascination with arthropods!).