The Tyrannosaurus goes after Ariel and Flounder and they think that if they swim, the dinosaurs won't get them. However, the Tyrannosaurus can breath on land and sea as he is shown aquatic. The trident beam must have gave the dinosaurs aquatic powers when they were unfrozened.
The Tyrannosaurus, Stegosaurus, and Triceratops go on a rampage in the vacation area and Sebastion almost got crushed by the T-Rex. The T-Rex thinks some objects are prey, the carnivore eats everyting in his path. A family of humpback whales came and they scare off the Stegosaurus and Triceratops. The Tyrannosaurus Rex battles the whales, but one huge male hits the T-Rex with his tail and it knocks out the dinosaur. Ariel thanks the whale for rescuing everyone. The Tyrannosaurus couldn't stand anymore of whales so he heads back to land with the Triceratops, the Stegosaurus, and the Brontosaurus family.