In Jaws, Steven Spielberg mastered the art of using sound to make an audience tense up instantaneously—thanks to John Williams’ iconic score. But in Jurassic Park, Spielberg created yet another indelible combination of image, sound, and dread: the approach of the deadly Tyrannosaurs rex, foreshadowed by ripples in water glasses sitting in the cupholders of the park’s branded Jeeps. To create the effects, supervisor Michael Lantieri describes putting motors in car parts to suggest the impact of a giant creature’s footsteps. The story behind the water ripples is even more clever, and involves a cleverly-placed guitar string in order to give the appearance of an approaching carnivorous dinosaur.