One belief unique to voodoo is the zombie. The creole word “zombi” is apparently derived from Nzambi, a West African deity but it only came into general use in 1929, after the publication of William B. Seabrook's The Magic Island. In this book, Seabrook recounts his experiences on Haiti, including the walking dead. He describes the first 'zombie' he came across in this way:
"The eyes were the worst. It was not my imagination. They were in truth like the eyes of a dead man, not blind, but staring, unfocused, unseeing. The whole face, for that matter, was bad enough. It was vacant, as if there was nothing behind it. It seemed not only expressionless, but incapable of expression."
Haitian zombies were once normal people, but underwent zombification by a "bokor" or voodoo sorcerer, through spell or potion. The victim then dies and becomes a mindless automaton, incapable of remembering the past, unable to recognise loved ones and doomed to a life of miserable toil under the will of the zombie master.
There have been some rare occasions of juju zombies temporarily regaining part of their mental faculties. This rare occurrence has only been observed when a zombie encounters situations that have heavy emotional connections to their mortal lives.
There are many examples of zombies in modern day Haiti. Papa Doc Duvallier the dictator of Haiti from 1957 to 1971 had a private army of thugs called tonton macoutes. These people were said to be in trances and they followed every command that Duvallier gave them. Duvallier had also his own voodoo church with many followers and he promised to return after his death to rule again. He did not come back but a guard was placed at his tomb, to insure that he would not try to escape, or that nobody steal the body. There are also many stories of people that die, then many years later return to the shock and surprise of relatives. A man named Caesar returned 18 years after he died to marry, have three children and die again, 30 years after he was originally buried. Another case involved a student from a village Port-au-Prince who had been shot in a robbery attempt. Six months later, the student returned to his parent’s house as a zombie. At first it was possible to talk with the man, and he related the story of his murder, a voodoo witch doctor stealing his body from the ambulance before he reached hospital and his transformation into a zombie. As time went on, he became unable to communicate, he grew more and more lethargic and died.
A case reported a writer named Stephen Bonsal described a zombie he witnessed in 1912 in this way: a man had at intervals a high fever, he joined a foreign mission church and the head of the mission saw the him die. He assisted at the funeral and saw the dead man buried. Some days later the supposedly dead man was found dressed in grave clothes, tied to a tree, moaning. The poor wretch soon recovered his voice but not his mind. He was indentifed by his wife, by the physician who had pronounced him dead, and by the clergyman. The victim did not recognized anybody, and spent his days moaning inarticulate words.
http://zombies.monstrous.com/voodoo_zombies.htm