The Tyrannosaurus Rex is the another main villain in "The Rite of Spring" segment and in the 1940 film, Fantasia. Like most non-talking animal villains (such as The Rat from Lady and the Tramp, The Bear from The Fox and the Hound, all carnivores from Dinosaur, and Sabor from Tarzan) the T-Rex does not show off that it intends to kill for evil (like a wicked grin or a laugh), helping audiences to understand that it just wanted to eat, but it's horrifying looks answers to why it is a villain otherwise.
The Tyrannosaurus attacks the herd of dinosaurs and a Stegosaurus fights it. After a long battle, it gains the upper hand and kills the Stegosaurus by biting it's throat, therefore crushing it. After the Stegosaurus dies, with all the other dinosaurs watching, the Tyrannosaurus roars in victory and then it eats. Near the end of the segment, it dies along with the rest of the dinosaurs do to mass dehydration as the earth climate changes.
Tyrannosaurus Rex is seen as The Disneyland train travels to the Primeval World diorama. In it, it is seen reenacting his battle from Fantasia.
In real life, Tyrannosaurus lived in the late Cretaceous Period 68-65 million years ago. Thus, it did not coexist with Stegosaurus, which lived in the Jurassic Period from 150-145 million years ago. Unlike in Fantasia, it did not have three fingers; it had two. Why it had three fingers is because Walt Disney reported to Barnum Brown, the discoverer of Tyrannosaurus, that it looked better that way.
Role in the series
The T-Rex is a monster of the Villain League alongside the Bear, Hydra, and Carnotaurs. It was originally a no show unoffitcal, but it then made a canon debute in the SAF comics in "A Prehistoric Surprise for Junjie".