The Poseidon Rex appeared in the movie of the same name, though there could be more. They have large fins that stretch from the tip of their snouts to the end of their tails as well as a pair of webbed feet and hand that allow them to swim. The aquatic adaptations actually saved them from the extinction event that killed most of the dinosaurs, and once the full evolutionary course came and went, they remained unchanged for millions of years. Although fish, sharks, dolphins, and small whales make up the bulk of their diet, they occasionally go towards land during the mating season (June to November) to feed on land animals, making them a nightmare for beachgoers and seaside communities.