LOL! It sure looks like a nitrous destroyed piston, doesn't it? Nope, no N20 on the Jeep.
The plug was tight when I checked it. I'm wondering if it had a bad injector causing it to lean out on that cylinder. I checked the records that the previous owner had given me last December. It was brought in at 200K for a "rough idle" issue. The dealer installed plugs, cap and rotor and wires, cleaned the throttle body and checked fuel pressure. The mechanic stated that it still runs rough and further diagnoses was necessary. As far as I know, this was the last time the plugs were changed. It has 223K on it now.
This Jeep has a massive class IV hitch on it. I wonder if they just flogged it to death in the mountains here while towing a motor home and without shifting down and on cheap gas. The rear springs are sagging bad too. I'll check that exhaust valve tomorrow and see if it's bent.