Can someone identify this odd looking spider?
I agree with JulPal's comment from August.  It looks very much like a male Thiodina (now renamed Colonus) sylvanus.  As with many Salticids, the females look rather different, and it turns out that there is apparently a similar species of Colonus in the area, which can be distinguished in the field by the fact that the white mark on the carapace is not a block so much as a thick longitudinal line.
I attach an image from Tree of Life, with the link below:



http://www.tolweb.org/Thiodina_sylvana/5911