Need a trailer hitch ball for my ATV

I went walking around the yard a little while ago looking on bumpers of vehicles we have (and yes, ones belonging to my brothers and nephews that are parked in the yard ::innocent look::) for a trailer hitch ball that I could swipe for using for a few days on the back of my ATV.

My brother has an ATV trailer that is parked out here in our yard at the moment and I have plans to use it for moving things around the yard. Trouble is, of the four trailer hitch balls I found, only one would budge and it spun the ball when I tried to get it off. I need a chain wrench that I can slap around the ball so that when I smack the crescent wrench with the heavy monkey wrench it don't move the ball too.

I'll probably just go buy a ball for the ATV, but am still going to try again to get the one off the old truck first. No sense buying a new one if there is one that is not being used sitting here in the yard, huh?