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.
If you will load iNaturalist app on your phone, you can snap a pic from in the app and with that and your location, it can usually predict the species or at least the genus. I don’t know southern Illinois, but I’d guess it is a variety of nettle.