Dennis Theodore Nedry was the main antagonist during the first half of the original Jurassic Park film. He was a computer programmer at Jurassic Park. Due to his financial problems and low salary, he accepted a bribe from Biosyn to smuggle Dinosaur embryos off the island.
In both the film and the novel, he is slain by a Dilophosaurus. He was directly responsible for the events that happened in both the novel and film. A combination of factors led to his demise: despite working in a career around dinosaurs and other prehistoric creatures, he had a limited knowledge of them, and greed, which was intertwined by desperation to pay off his debt collectors and make himself rich after that.