The horror film Jaws (Spielberg, 1975) terrified millions of movie-goers and continues to resonate with audiences, despite its implausible premise and zoologically dubious depiction of a vengeful great white shark. An evolutionary approach explains why the film captured audiences’ imaginations and produced in thousands an abiding, profound terror of the sea. Jaws gets its peculiar power from successfully immersing its audience in a primal scenario of predation by a malevolent animistic agent, the shark. The representation of the shark exploits the structure of evolved hazard-precautionary cognitive architecture. The shark is salient and narratively dominant, yet it has very little screen time. By shrouding the shark and its whereabouts in uncertainty, Spielberg amalgamates the evolved fear of predation with the evolved fear of the unknown. That joint fear response is compounded by sympathetic anxiety for vulnerable characters in peril. Jaws fulfills the function of horror, which is to provide consumers with an occasion for imaginative immersion in a fear- and anxiety-provoking scenario. The film derives its power from effectively engaging ancient, evolved defense mechanisms in human nature and from satisfying an adaptive desire for extreme vicarious experience.