ZOMBIES ARE HERE . . .

A zombie is traditionally an undead person in the Caribbean spiritual belief system of voodoo. Essentially a dead body re-animated by unnatural means, the zombie creates dread among the living. Zombies have become a staple of horror fiction, where they usually engage in the consumption of human flesh. The term "zombism" is sometimes used to refer to the condition or disease associated with being a zombie.
 

Zombie powers
Zombies never sleep, and they are incapable of fatigue.
Zombies are impervious to pain and require no air to breathe.
They are thus immune to drugs, poisons, gases, extremes of temperature and pressure, high voltage electricity, suffocation, and drowning.
While not invulnerable to physical injury, zombies can suffer great damage to their bodies (including dismemberment) without being adversely affected. Dismembering the legs will render the zombie immobile, but the creature will still continue to subsist. Likewise, decapitation will incapacitate the body, but the head will still "live".
Zombies don’t possess any superhuman strength, nor do they have a night vision, a characteristic usually common to undead monsters.

Walking dead
“walk or die” has been replaced by “die and walk”. The most terrific aspect of the zombie is that it first appears as the casual shape of a typical civilian which mind has been sucked out and left empty. Zombies are terrific because instead of delicately sucking your blood as the vampire, they come in disguise and brutally tear you into pieces. The deactivation of a zombie's nervous system, caused by the curse or chemical and genetic alterations, has often been used to explain their very low mobility and rate of metabolism. The chemicals in the human hypothalamus acts as a stimulant for their metabolism, prolonging their not-quite-dead condition.

Craving for human flesh
Zombies created by voodoo tend to be harmless, and are often used as slaves by the witch doctors that have created them. In spite of its rather feeble intelligence, the hollywood zombie is a both intellectually and physically driven only by his all-consuming hunger for fresh human flesh. Why the dead are so hungry for living flesh is still unclear?. As a slightly potty researcher illustrates in Day of the Dead, the dead do not need to eat, they reach for live flesh even when they have no mouth or gullet, even when their stomachs have been removed. The impulse is part of their very fibre, a spiritual craving. They are dead, and death wants to consume life. It is an image of insatiable nihilism that is hard to resist. In Romero’s trilogy and sequels, the world has discovered that these zombies are particularly fond of human brains, requiring the chemicals in the hypothalamus for maintaining their existence.