Gallimimus

A herd of running Gallimimus appears in the first Jurassic Park film, taking the place of the novel's Hadrosaurus. The scene was rewritten several times: final screenwriter David Koepp swapped in Gallimimus on Phil Tippett's advice.

ILM created the Gallimimus entirely in CGI, and it was the first dinosaur digitized during production, so it served as a test of whether animating dinosaurs digitally was possible at all. Animator Eric Armstrong built one Gallimimus skeleton, animated its run cycle and duplicated it into a herd, tweaking each copy slightly so the animals looked distinct. The skeletal test over a jungle background worked, which led to a second test with fully skinned Gallimimus and a T. rex.