CCTV News reported that a woman in Shandong Province, China, was shocked to discover that a slab of beef she had just purchased from a local market appeared to be pulsating like a beating heart.
Instead of eating it, the woman (wisely, I'm sure) chose to record the moving, pulsating meat that the Internet has dubbed "Frankenstein meat". Here's the video (WARNING: Not for the faint of heart - the video is probably not suitable if you don't have the stomach for gross stuff)
Some people have suggested that the reason the meat pulsated like that is because it's so fresh the nerve endings are still active.
as a foodie, I know that most beef is hung for several days to months to cure.
So if I had to guess, this wiggling is either due to hoax, which is what I think it is OR it's full of maggots or bugs of some sort like in Poltergeist as Daniel suggests.