Ok, this one is kind of gross, and kind of neat! It’s a group of animated rats eating a leg. Yummy! Check out the web site for pictures of the build and a movie of the final prop.
The pictures pretty much tell the story of this prop. A small motor turns a crank (or two in this case), wires are connected to the crank using ring terminals and then routed through eye hooks to each rat. The rats have their tails screwed down to the base board. Because of the design of the rats, this lifts their front feet off the board about half an inch. When the motor rotates, the flexible vinyl rats get pulled down as if they are taking a bite out of the flesh and as the motor comes back around they return to their original position.
More about the Motorized Rat Feast