This thread make me LOL. I agree with casey though, MJ only made the public aware of the dance it was the choreographer who created it. Copyrighting a dance would be rather insane.
Take a moment to consider the carnage if all dances were copyrighted. We would all likely end up suffering from depression as we would never be able to do the Conga, the Macarena, Saturday Night Fever or any of those other dances you love... the Music Man lol.
On a more serious note though the likelihood of MJ creating a law suit is slim to none as he wouldnt have a legal leg to stand on. Hes more likely to create an account and then begin to broadcast the fact over RS that he made the zombie dance famous and would anyone like to come to his POH to play.