 The crew moved to Warner Bros. Studios ' Stage 16 to shoot the T. rex 's attack on the LSX powered SUVs . Shooting proved frustrating because of water soaking the foam rubber skin of the animatronic dinosaur , which caused the animatronic T. rex to shake and quiver from the extra weight when the foam absorbed the water . This forced Stan Winston 's crew to dry the model with shammys between takes . On the set , Malcolm distracting the dinosaur with a flare was included at Jeff Goldblum 's suggestion , as he felt a heroic action was better than going by the script , where like Gennaro , Malcolm would get scared and run away . The ripples in the glass of water caused by the T. rex 's footsteps were inspired by Spielberg listening to Earth , Wind and Fire in his car , and the vibrations the bass rhythm caused . Lantieri was unsure of how to create the shot until the night before filming , when he put a glass of water on a guitar he was playing , which achieved the concentric circles in the water Spielberg wanted . The next morning , guitar strings were put inside the car and a man on the floor plucked the strings to achieve the effect . Back at Universal , the crew filmed scenes with the Dilophosaurus on Stage 27 . Finally , the shoot finished on Stage 12 , with the climactic chases with the raptors in the Park 's computer rooms and Visitor 's Center . Spielberg changed the climax to bring back the T. rex , abandoning the original ending in which Grant uses a platform machine to maneuver a raptor into a fossil tyrannosaur 's jaws . The scene which already had the juxtaposition of live dinosaurs in a museum filled with fossils , while also destroying the bones , now also had an ending where the T. rex saved the protagonists , and afterwards did what Spielberg described as a " King Kong roar " while an ironic banner reading " When Dinosaurs Ruled the Earth " flew . The film wrapped twelve days ahead of schedule on November 30 , and within days , editor Michael Kahn had a rough cut ready , allowing Spielberg to go ahead with filming Schindler 's List . 
