Composer Mark Korven, who scored modern horror legends like 'The Witch,' felt that digital samples weren't scary enough. He commissioned luthier Tony Duggan-Smith to build 'The Apprehension Engine.' This custom instrument is a nightmare-inducing machine made of metal rulers, long wires, a spring reverb, and a rotating crank. It is designed specifically to produce sounds that trigger a primal fear response—dissonant screeches, deep rumbles, and metallic moans. Unlike a traditional instrument, there is no way to play a 'pleasant' melody on it. It has since become a legendary tool in the horror industry, used to create the sonic atmosphere of dread that accompanies modern movie monsters. It proves that sometimes, a custom-built instrument is necessary to translate a director's terrifying vision into sound.