Twitch of the Death Nerve (Italian: Ecologia del delitto, also known as Blood Bath, A Bay of Blood and Reazione a catena), is a 1971 Italian horror film directed by Mario Bava. Bava cowrote the screenplay with Giuseppe Zaccariello, Filippo Ottoni and Sergio Canevari, with story credit given to Dardano Sacchetti and Franco Barberi. The film stars Claudine Auger, Luigi Pistilli and Laura Betti. Carlo Rambaldi created the gruesome special makeup effects. The story details the simultaneous murderous activities of several different characters as they each attempt to remove any human obstacles that stand in the way of an inheritance. Easily Bava's most intensely violent film, its emphasis on graphically bloody murder set pieces was hugely influential on the slasher film subgenre that would follow a decade later. In 2005, the magazine Total Film named Twitch of the Death Nerve one of the 50 greatest horror films of all time.