Giant Platypus

Giant platypus (Megaornithorhynchus giganteus) is one of the few platypus species, and they are the same size as a saltwater crocodile, making them the large monotremes that ever existed. They are carnivorous, preying upon fish, Jack's giant wombats, demon dragon eggs, emus, feral camels, and humans (sometimes). Their rivals are demon dragons, drop bears, modern thylacines, saltwater crocodiles, and modern marsupial lions. Just like their smaller relatives, they are semi-aquatic.