Probably some monk during the Black Plague while he was preparing a body. Must've given him a shock when the air from the deceased's lungs was pushed out and vibrated its vocal cords. Rigor Mortis is pretty strange.
I'm not sure if this explains zombies; but I'm pretty sure it explains vampires. The body swells, which gives it the appearance that it has been feeding. Its hair and fingernails appear longer, which is because they do continue to grow for a bit after death and the absence of some skin makes them look bigger. Finally, their deathcowl appears to be chewed through and his bloody, suggesting a recent feeding. This is because blood coming from the mouth rots the deathcowl. Sorry if this paragraph got a bit too off-topic.
I thought they were born out of the voodoo tradition in Jamaica.
What you're reffering to are voodoo zombies. Who are created when a voodoo priest uses zombie powder on a person. Zombie powder is a nerve toxin or something of the sort. It gives the victim the appearance of death. The victim's motor are severly affected which gives them the appearence of "zombies."
The idea of zombies is not cool. A dead human corpse walking at you only to bite you and rip you apart is not a cool idea to me, and the smell of rotting flesh is horrible.
honestly if a time comes that zombies rise up out of the ground and try to exterminate us, all the people who play call of duty zombies are not going to be any kind of help when they come. They might even be the first ones to die.
Really, I would just look it up at Wikipedia, but I'm too lazy too... xD
Very Lazy considering the link was only a few posts up.
The idea of zombies is not cool. A dead human corpse walking at you only to bite you and rip you apart is not a cool idea to me, and the smell of rotting flesh is horrible.