The zombies seen in modern Western works are often based on medieval European revenants, who were recently deceased individuals rising to harass their families. Later revenant stories involved victims or perpetrators of crimes like murder. The modern zombie genre was influenced by Richard Matheson's novel "I Am Legend" and George A. Romero's film "Night of the Living Dead", which depicted zombies as cannibalistic and nearly unstoppable. Zombie stories can examine issues like racism, consumerism, and military conflicts through the metaphor of a zombie apocalypse.