Zombies

Zombies, mostly referred to in-universe as walkers, monsters, roamers, geeks, lurkers, biters, muertos, infected and empties, are an antagonistic force that serve as the primary catalyst for the events within The Walking Dead universe. They serve as universal antagonists.
== Overview ==
Reanimated human beings, while not immortal, will not "die" under typical conditions that would ordinarily cause the death of a living person. They do not appear to feel or respond to pain, can survive even the most brutal injuries, and despite their bottomless appetite for flesh, they do not need food, water, or sleep to function.
They show no other bodily function that relates to a human, showing no signs of self-healing or response to extreme temperatures. The brain maintains limited abilities of the body, allowing for movement of the limbs (provided that they are not decomposed to the point where the bones are not strong enough to bend without breaking), jaws, neck, and even the use of its sensory systems. While the walkers are notoriously weaker than humans, the only way to kill one is to destroy the brain. Despite severely weakened frames, they will continue to hunt for living animals to consume. Even when decapitated, the head will remain active, even though it would be practically harmless at such point.
== Nicknames ==
While the term "zombie" does exist within The Walking Dead universe, it is seldom used. In the Comic Series, when Rick Grimes' group discover the prison, both Rick and Tyreese discuss how it still sounds funny to use the word "zombie." Likewise, in the Telltale video game, the term is used very rarely.
"Zombie" has not been used in the TV series; when interviewed, Lauren Cohan stated that Romero movie zombies never existed in the popular fiction of the TV Walking Dead universe. The characters within The Walking Dead TV series and comic books come up with their own monikers and categorizations for the undead.
The term "zombie" originated with the Haitian practice of voodoo and refers to a person who is reanimated as a slave in the thrall of another person. Those zombies are still clinically alive and can be restored, where the "walkers" of The Walking Dead are in fact dead, presumably not under any control, and cannot be restored.
Despite the fact that the idea of zombies was never a thing in the TV Universe, and thus the term would never have been popularized, the Waitress tells Troy that the quesadilla contains "antojitos zombie".