As fictional undead creatures, zombies are regularly encountered in horror and fantasy themed works. They are typically depicted as mindless, reanimated corpses with a hunger for human flesh, and particularly for human brains in some depictions. Although they share their name and some superficial similarities with the zombie from Haitian Vodun, their links to such folklore are unclear. Many consider George A. Romero's film Night of the Living Dead to be the progenitor of these creatures.[15][16] Zombies have a complex literary heritage, with antecedents ranging from Richard Matheson and H. P. Lovecraft to Mary Shelley's Frankenstein, all drawing on European folklore of the undead. The popularity of zombies in movies has led to them sometimes having been taken out of their usual element of horror and thrown into other genres, for example the comedy film Shaun of the Dead. The "zombie apocalypse" concept, in which the civilized world is brought low by a global zombie infestation, has become a staple of modern popular art. By 2011 the influence of zombies in popular consciousness had reached far enough that the United States government's Center for Disease Control used the idea as a theme to promote disaster preparedness