Via MTV Multiplayer, it looks as if we are to soon lose the Michael Jackson-inspired dancing zombie. Displaying both his outfit and moves from the Thriller video, the zombie would summon forth four other dancing zombies and perform the signature 'raised arm' dance from the video (available for your viewing here).
For those who own the iPhone version, the change has already occurred to have a disco zombie. The change is coming due to a request from the Michael Jackson estate. In response to Russ Frushtick's query to PopCap, here was the response:
The Estate of Michael Jackson objected to our use of the 'dancing zombie' in PLANTS vs. ZOMBIES 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 PLANTS vs.ZOMBIES on all platforms. The phase-out and replacement process is underway.
As Frushtick points out, legally PopCap could probably get away with saying this falls under the realm of parody, but has made a decision to respect the late Michael Jackson, and is in the process of phasing out his zombie. Beyond parody, I saw it as an homage to Jackson, so I guess I don't see the large problem with the resemblance. Then again, I tend to be irreverent in a lot of situations.
One further note is that those with the iPhone 4 may wish to hold off on updating, as the game appears to be crashing. This only affects those updating, and not those purchasing and downloading the latest version.