Like all dinosaurs in the novel, the Tyrannosaurs were created by Lord Darren Penward which has found dinosaur DNA fragments in fossils and has used them as a basis for restructuring the DNA of chickens.
They appears at the end of the novel when Sir Penward imprisons his wife in a farmhouse where she is devoured alive by two newly hatched Tyrannosaurs. The baby Tyrannosaurs are the only dinosaurs to be still alive at the end of the novel aside from a baby Brachiosaurus.
In the film, the dinosaurs were created by a scientist named Jane Tiptree by combined iguanas, crocodiles, albatrosses, vultures, pelicans, turkeys, ostriches, and dinosaurs' DNA (where the dinosaur DNA acquired from fossils) where the combined DNA eventually used to create a breed of extra large chicken. The said chicken later give birth dinosaurs, includes Tyrannosaurus and Deinonychus. During the film, sends one of his co-workers to get devoured by the T-Rex.
Near the end of the film, Doc, the main protagonist of the film, discovers the Tyrannosaurus in the lab of Tiptree. The dinosaur attacks him, but he flees and manages to narrowly escape him, and also to get away from the lab. However, the Tyrannosaurus breaks a wall and pursues Doc.
Doc gets into a skid steer and use it to battle the Tyrannosaurus. Unfortunately the reptile reverses the vehicle and tries to devour Doc, but his friend Thrush arrives on another skid steer and injures the Tyrannosaurus's leg. Doc then gets into the skid steer and manages to kill the Tyrannosaurus with it.
The Tyrannosaurus is one of the cloned dinosaurs who have been hidden in a nuclear mining facility after the events of the first film.
Near the end of the film, Jesse and Jack, the two main protagonists, go to the surface in order to take a rescue helicopter to be able to leave from the nuclear mining facility. However, they encounter the Tyrannosaurus, which immediately attacks them. Fortunately, they manage to escape in an elevator and come to the surface.
Shortly after, the Tyrannosaurus arrives by breaking a wall and devours one of the members of the rescue crew. Jesse gets behind the wheel of a forklift and confronts the dinosaur. Finally, he succeeds to push him to the bottom of the elevator shaft, killing him.
Carnosaur 3: Primal Species
A female Tyrannosaurus is one of the three dinosaurs which have been frozen in an army convoy, along with two Velociraptors.
However, some terrorists (whom mistaking their container filled with nuclear chemicals) attack the convoy and accidentally release the dinosaurs. They kill most of them and later goes on a massive meat shipment. The Tyrannosaurus is revealed to be pregnant and lays many eggs aboard the ship.
Afterwards, a military team led by Colonel Rance Higgins infiltrates the ship in order to kill the dinosaurs with dynamites. There, they discover the nest and begin to shoot, which causes the Tyrannosaurus to become mad and she kills some of them. Rance and a few others are then pursued by the Tyrannosaurus and hide behind lockers which the reptile head-butts. Rance finally throws an explosive in the mouth of the dinosaur, killing her. The ship explodes soon after.