Who is this thorny plant friend?

I thought I knew all the plants that would attack me in southern Illinois...then I headed off trail to find a good spot for a cathole and started to push through a shoulder-high thicket of these guys:

This proved to be a mistake, due to the hitherto-unnoticed-by-me spiky thorns all over their stems. I found another spot, so now I'm just left with small punctures & curiosity.