Felix Culpa passes on the Orthodox word on the undead. Apparently, certain questions were posed Iosaph of Ephesos, (14th century) about the then prevalent version of vampires and zombies.
Iosaph, in responding to the question of whether there really are female vampires who suck the blood of, and kill, infants, writes that this belief is the result of "a confusion of the devil" and therefore should be rejected
Apparently, vampires were only female back then.
According to Fr Patrick, Ioasaph's central concern centers on the relationship between female vampires and blood, because in late Byzantine canonical texts "blood is frequently presented as a woman's chief contribution to human birth, particularly in discussions related to unborn children such as regarding abortion.
Those who believe in zombies are, according to Ioasaph, themselves under demonic influence.
Ioasaph seems to be presenting the undead as disorder representations of humans. Meanwhile, I see the modern day versions as a corruption of Christ's story. There are now plot lines with good vampires trying to save us poor humans, and I've seen a few atheistic cartoons depicting Our Lord as a zombie. The modern day horror genre seems to equate rising from the dead with mindless evil and immortality and power with cannibalistic murderers.
Felix expands the discussion to all other sorts of imaginary creatures:
It could be argued on the basis of the points made above that such fantasies, even when intended to encourage virtue, nonetheless predispose readers (children, especially) to belief in, so to speak, a non-incarnate reality. This, in turn, can become a medium for demonic temptation.
An interesting conclusion. Go forth and read it instead of relying on my chopped up little diversion here.