Inside the popular game of Plants vs. Zombies, the almanac entry for the "dancing zombie" states that "[a]ny resemblance between Dancing Zombie and persons living or dead is purely coincidental." The estate of Michael Jackson didn't agree. They felt that the light-hearted homage wasn't a thriller in regards to Jackson's memory. They found it too close an imitator as far as copyright infringement goes. Or something like that. But let's not split peas over the matter.
According to a PopCap spokesperson, the estate objected to PopCap's use of the "dancing zombie" in PvZ based on its view that the zombie too closely resembled Michael Jackson. After receiving this objection, PopCap made a business decision to retire the original "dancing zombie" and replace it with a different "dancing zombie" character for future builds of PvZ on all platforms. PopCap tells TUAW that the phase-out and replacement process is underway, which is what you are seeing in the App Store updates; presumably the Mac and Windows versions are also due for tweaking.
So it looks like a new star-powered zombie will be stepping under the dancing umbrella-ella-ella from this point forward. As for us, we'll be starting with the zombie in the mirror. (And asking him to stop gnawing on our skulls.)
P.S. Billie Jean is not my Zombie. She's just the plant who thinks that I am the one...who can get zombies off her lawn...
P.P.S. More coverage here and here.
RIP MJ Zombie