At 16 inches (41 centimeters) long, it was perhaps the largest, not to mention, most obese frog to ever have hopped across a Cretaceous lily pad. When scientists found the remains of this fossilized frog in Madagascar, they were agog at its size. Known as the Beelzebufo ampinga, or "devil frog," it was 3.5 inches (8.9 centimeters) taller than the largest living frog ever found. It lived between 65 and 70 million years ago, right in the thick of the Cretaceous. The devil frog had an overly large mouth and stomach. It was so huge that it probably didn't do a lot of hunting on its own, but rather waited until its prey passed by. What did it eat? Smaller frogs, lizards and mice, and perhaps, just perhaps, baby dinosaurs [sources: Moskowitz, National Geographic].
Other amphibians also thrived during the Cretaceous. One was Koolasuchus, a half-ton giant with eyes on the top of its head. It was a tetrapod, or four-footed, vertebrate that liked to hang out in cooler regions but didn't fare well when Earth warmed [source: BBC].