Zombie was a term employed to refer to human corpses that had been reanimated through unknown means.
== CANCER CELLS
A zombie continues to change throughout its existence by exposing many differences in terms of appearance and behavior. All zombies show large amounts of physical strength when active, but seem as ill as they are when passive.
The first stage of zombification is the common, undecayed zombie. Most zombies shown in the film are still in the first stage. They lack the rotten skin that is a characteristic of the transition, but may still have wounds and the typical bluish-purple of cold, bloodless skin. First stage zombies show submission to the Bonnies and act indifferent to Transition-stage zombies. R and M can be classified as First-stage zombies.
Transition, or Fleshy zombies are your typical classical zombies, with a decaying look. They feature prominant exposure of rotten flesh and internal parts which as bone that many zombies in popular culture are depicted as. The decayed flesh on their bodies is blackened and there is no evidence any blood is present in their bodies. They have the classical zombie look.
Bonies are a blackish-blue hue, and are only skeletons. They were once zombies, but eventually decomposed completely and only their bones were left. They are also shown to be much lighter on their feet than the zombies.
At the beginning of the film R comments says, "They'll eat anything with a heart beat. I mean, so will I, but at least I'm conflicted about it." This suggests they lack any moral centre and are ultimately lost on a human level, being completely zombified. This is evident, as they served as a primary antagonist in the film. Bonies exhibit extremely aggressive behaviour and are feared even within zombies.
The only way to kill a zombie was to permanently sever the brain's communication with the body. This could be achieved through decapitation or completely destroying the head or brain.