I found one of the Midgets free roaming in the Freakshow Tent once, so I beat him up. Down he goes, and pops back up again. Beat him some more, same thing. Haul out the Spud Gun, shoot him 3 times, down and pops back up, and so on and so on....
So, if the little fucks aren't in the ring, they're like the dogs, can't keep 'em down.