Aliens and the Undead (S03E14)

Zombies rising from their graves...Blood sucking vampires damned for all eternity... and humans trapped in a life and death struggle between heaven and hell. For thousands of years, mankind has told tales of encounters with strange, soulless creatures. Are these beliefs rooted in more than just mere myths? Ancient Egyptians used a Book of the Dead to transition between death and rebirth. Chinese legend speaks of zombie-like creatures called Jiang Shi that hunt their living relatives. The Zapote Indians worshiped a bloodthirsty Mayan God with the body of a man and head of a bat. Are these beliefs merely manmade fabrications - or could there be extraterrestrial origins in earthly encounters with the undead? (iTunes)