Paleontologists have discovered a giant frog in Madagascar that lived 65-70 milllion years ago. My favorite part of the story is that they named the frog Beelzebufo. This devil of a frog measured around 20 centimeters across and was 40 centimeters long. From Nature News:
The team couldn't piece together a complete skeleton, but did get a nearly complete picture of the skull, which was "short and fat with a huge mouth", says (University College London scientist Susan) Evans.
Similarly-shaped South American frogs have a strong bite and can feast on small vertebrate such as mice and lizards: "Basically, they eat anything smaller that walks by," Evans says.