Vastatosaurus rex is the largest predator on Skull Island, reaching lengths of up to 70 feet and weighing around 15 tons. Vastatosaurus rex represents what Tyrannosaurus rex would have become if the species was allowed to evolve unabaited for another 65 million years. Like their prehistoric relatives, Skull Island V. rexes have little competition for their position as top predators. Their only enemies were the giant apes that lived in the mountains, known as Megaprimatus kong.