The Paleocene era would have been a terrible time to own a pet turtle, unless you had a garage to park it in. Paleontologists have discovered a car-sized turtle in a Colombian coalmine that may have eaten alligators and ruled a large swath of land and fresh water. After the Great Extinction that wiped out the dinosaurs 65 million years ago, reptiles continued to thrive, with some of them, like the 40-foot Titanoboa, growing to enormous sizes and dominating the post-apocalyptic epoch. This titanic turtle, dubbed Carbonemys cofrinii, was a Titanoba contemporary, at the size of a Fiat with a skull as big as a football. And in an era where ancient crocs preyed on small turtles, this 6-foot shell-dweller flipped the predator and prey relationship. How did creatures like this get so big? Scientists think the lush, hot environment helped—as did a lack of predators. So, we’ve got the mutant turtles—now, we just need to figure out if they liked pizza and knew kung fu. Video produced by Paca Thomas.