Ok but for real, that wouldn’t work, right? How would them holding it complete the circuit? The circuit is just gonna be from one screw to the top of the pole back through another screw, not the part the person is holding.

I mean, a car battery isn’t going to do anything even if you could complete a circuit. You can just grab the terminals on a car battery, 12V isn’t high enough to be noticeable on dry skin.

You’d want to solder on the hot lead of an extension cord hooked up to 120 if you wanted to make sure they never touch that pole again.

Disclaimer: don’t do this, it’ll probably kill.

A electric horse fence is a better option. Will zing you but isn’t lethal and also has an intermittent current. Specifically designed to be touched by living things without harm. But stay away from cattle fencing, that can kill someone with a heart condition.
You would have to try pretty hard to kill yourself with a hotwire even if you had a heart condition. Like lay on your side on the ground and grab the hotwire so maybe the circuit went through your heart and not entirely followed the shortest path to ground along your side.