As if platypuses weren't weird enough already, scientists in Australia have come upon a fossilized tooth of what they're calling "platypus-zilla"—a creature some three feet long, or at least twice the size of your everyday platypus. "It probably would have looked like a platypus on steroids," says researcher Mike Archer, citing a "gigantic monstrosity that you would have been afraid to swim with." But the find, which lived between 5 million and 15 million years ago, won't just haunt researchers' dreams; it reveals a lot about the evolutionary history of the platypus, the BBC reports.
Scientists had thought "maybe it was just one lineage of strange animals bumbling its way through time and space at least for the last 60 million years," Archer says. Instead, platypus-zilla "indicates there are branches in the platypus family tree that we hadn't suspected before." The tooth's bumps and other local fossils suggest it ate crustaceans, fish, turtles, and frogs, the BBC notes; modern platypuses have teeth only while young, Australia's ABC News notes. (Read more platypus stories.)