I just updated my Plants vs Zombies on my ipod. The update said it had new achievements (which are awesome).
It did NOT mention that it replaced the Michael Jackson Thriller zombie with a zombie wearing a disco suit.
W...T...F...?!?
I figure they must have gotten sued because the description of the zombie in the almanac says "any similarities between this zombie and any person alive or dead is coincidental" or something to that effect.
This sucks. I really liked the Thriller zombie.
SO... if you want to keep Michael Jackson in your PvZ, do not update it!