Zombies are often portrayed as mindless and cannibalistic but sometimes intelligent which inspired by George A. Romero's works, zombies are type of undead monster or alternatively a being that is not dead, but unnaturally lived thanks either through infection with some strange virus or parasite that control their mind and motoric system once succumbed, or simply corpses that revived via necromancy or other dark magic with similar effects. In other case, zombies also created via mind-washing at hands of brainwashers or magical substance/influences that brough corpses (mostly).

However, not all zombies are undead: in fiction, some cases are shown that zombies can also be created via certain method of brainwash on innocent people that made them become mindless servants, either magically or mind control devices. Perfect examples of this are Voodoo Zombies, zombies that are actually humans that brainwashed via Voodoo ritual.