The Tyrannosaurus was portrayed as a huge dark blue/purple carnivorous dinosaur with a big square head and a mouth full of long, razor-sharp teeth. The one in Fantasia is incorrectly shown with three fingers, while the actual dinosaur only had two. Walt Disney himself knew that the real Tyrannosaurus had only two fingers, but thought a three-fingered portrayal would look scarier. In other appearances, Tyrannosaurus is often depicted as being colored red, green, brown, purple, blue, orange, gray, or black and is portrayed (correctly) with two fingers.
In real life, Tyrannosaurus rex was a genus of coelurosaurian theropod dinosaur that lived in the Maastarichtian stage of the Late Cretaceous Period, about 68-65 million years ago. Thus, it did not coexist with any species of Stegosaurus, which lived in the Tithonian stage of the Late Jurassic Period, from 156-145 million years ago. This puts a gap between the two species that is larger than the one that separates Tyrannosaurus rex from us! Unlike in Fantasia, Tyrannosaurus rex did not have three fingers; it only had two. Why it was portrayed with such an inaccuracy is because Walt Disney reported to Barnum Brown, the discoverer of Tyrannosaurus rex, that it looked scarier that way. Due to recent discoveries on related dinosaurs, some believe that Tyrannosaurus had feathers like Oviraptor, Velociraptor, and modern birds. Additionally, Tyrannosaurus did not walk upright with its tail on the ground, but stood horizontally with its tail sticking out straight behind it. Tyrannosaurus did however, as many media depictions and films accurately show, have a bite that could crush bone. In many films, T. rex is also depicted as having useless arms, but in truth, each arm could lift two grown men each. What its arms were used for however, remains to be seen, but many theories indicate that its arms were probably useful for holding prey or perhaps in attracting mates.
The Tyrannosaurus makes his first appearance as he attacks the dinosaurs of the lowlands. They all stare in horror in his general direction as rain begins to fall and lightning crackles when the massive theropod enters the scene. They immediately continue to retreat in fear as the Tyrannosaurus marches forward, snapping his jaws at anything that moves. While many of the smaller dinosaurs are able to retreat out of the hungry theropod's path, the Stegosaurus is unable to move away fast enough and is quickly targeted. The Tyrannosaurus latches his brawny jaws around the Stegosaurus' tail just above the spikes, dragging his heels into the mud and bringing the lumbering dinosaur's retreat to a suspenseful halt. The Stegosaurus faces his attacker who roars violently and quickly goes for the neck with his thick square jaws. In defense, the Stegosaurus lashes out with his spiked tail, trying desperately to keep the hungry theropod at bay. After a few brief lash outs and defensive volleys by the two titans, they begin to slowly sidestep each other. A short yet vicious battle follows and the Stegosaurus is quickly unable to stay on his feet as the Tyrannosaurus time and time again goes for the neck, fighting hard against the defending tail spikes of his prey. With the battle won and his prey fallen, the Tyrannosaurus lets out a mighty roars in victory as the other dinosaurs watch. With the struggle over and the predator satisfied, the other dinosaurs return to their business as the Tyrannosaurus gorges on his prize.
Near the end of the segment, the Tyrannosaurus makes an appearance just before he dies. The once mighty ruler of the Cretaceous succumbs to mass dehydration as the Earth's climate changes, visibly collapsing into the sand. Other dinosaurs, including a Parasaurolophus and a Ceratosaurus, pass the corpse and continue on into the hazed distance, a path that leads to nowhere but their own extinction.
He also makes a cameo in the sequel Fantasia 2000 fighting the Stegosaurus in a flashback from the original film.
In the episode "Land of the Dinosaurs", Ariel finds frozen dinosaurs during a trip to the North Pole, and she thaws them with her father's trident. King Triton makes a refuge for them on land after some dinosaurs cause chaos. A T-Rex was among the species of dinosaurs that were causing havoc.
A Tyrannosaurus Rex-like creature, christened "Skullasaurus" by Pooh and his friends, supposedly could be heard roaring inside Skullasaurus Cave as well as throughout the movie. However, the roaring was actually Pooh's rumbling tummy amplified by the echoes in the cave and by everyone's fears.
A brown Tyrannosaurus Rex was the main antagonist in the episode "It's About Time!" When Phineas, Ferb, and Candace were trapped in the Mesozoic era, a T-Rex chased them. They eventually lost it, but it found them again. When they were back in the present at the museum, the T-Rex accidentally came with them. It then attempted to attack Candace, but Doofenshmirtz's Freezeanator hit it and froze it. When the T-Rex is chasing Candace, the theme from the Tyrannosaurus Rex, Grumpy, from the 1970s television show Land of the Lost can be heard. The T-Rex made a cameo in "Mom's Birthday" from a flashback. It made two more cameos in "Unfair Science Fair Redux (Another Story)" and "Phineas and Ferb's Quantum Boogaloo".
In the episode "Land Before Swine," a number of dinosaur species are seen trapped in tree sap in the abandoned mines in the forest. The summer heat causes the tree sap to melt, slowly releasing all the dinosaurs from the sap. A T-Rex was among the species of dinosaurs trapped in tree sap. One T-Rex is later utilized by the rebels during Weirdmageddon as a part of the Mystery Shack robot.
In Walt Disney World's Magic Kingdom A T-Rex skeleton is seen in Where the train makes a right hand turn, and passes through the T-Rex's ribcage as it hits the final trim brake.
In Walt Disney World's Epcot, there is a ride known as Ellen's Energy Adventure, starring Ellen DeGeneres and Bill Nye the Science Guy who explore the world of energy, including the use of fossil fuels. During the ride, Bill Nye brings DeGeneres "back in time" to the age of dinosaurs to explain the origin of fossil fuels. During this portion of the ride, several dinosaurs can be seen that are similar to the ones during Fantasia'sThe Rite of Spring. Most notably, there is a large Tyrannosaurus attacking a Stegosaurus over a cliff. This is obviously in reference to Fantasia.
In Walt Disney World's Disney's Animal Kingdom Some T-Rexes can be seen in DinoLand USA. There's a Skeleton Replica of SUE The Largest & Most Complete T-Rex to date, A Life sized replica of a Tyrannosaurus Rex along with a life sized replica of an Albertosaurus in Cretaceous Trail & a Life sized Head & Neck of a T-Rex seen at the near Entrance of the Ride Attraction DINOSAUR.
In real life, Tyrannosaurs Rex and Stegosaurus would never have met, as Stegosaurus lived 80 million years early in the Jurassic period, while Tyrannosaurs Rex lived at the end of the Cretaceous period.
During the production of DINOSAUR, then called Countdown to Extinction, original plans called for Tyrannosaurus Rex, but Disney decided to incorporate the later newly-discovered Carnotaurus instead. Also, in the original story for Dinosaur conceived and pitched by Phil Tippett and Paul Verhoeven in 1988, the main antagonist was going to be a Tyrannosaurus named Grozni.
On Disc 1 of Disney's Dinosaur: 2-Disc Collector's Edition in Fossil Dig, the bonus feature called "3-D Workbook Opening Sequence" (from the animated sequence of the alternate film's opening) showed a meat-eating dinosaur that appeared to have been a Tyrannosaurus Rex, which was defiantly originally planned in the film's sequence before Carnotaurus was put in the movie instead. Additionally, on Disc 2, there are a few concept art images called "Carnotaur Design and Unused Character Concepts."
A Christmas gag sketch produced for Disney Studio's internal newsletter in 1939 featured the Tyrannosaurus from Fantasia in a Santa suit and nicknamed "Mr. S. Twombley Tyrannosaurusclauses."