There are many unusual town names here in Tennessee; I just heard about this one!
This is a photo of the side of the general store in Skullbone.
Skullbone, which doesn't appear on some maps now, was the site of long-ago fist-fighting competitions in which bare-knuckle boxers could only deliver blows to their opponents' heads. It was called "skullbone" fighting, and the name stuck to this unincorporated hamlet.
The sign was placed by the locals for all the tourist that comes through. Back in the day people would come in from everywhere to fist fight.