This is an item that's been in my 'how cool is that?' folder for a while – a very large dinosaur-eating frog!
Well, possibly dinosaur-eating – we've no information one way or the other. 'Beelzebufo' (devil frog, or frog from hell) was certainly big enough to eat a hatchling or a juvenile dinosaur – researchers described it as roughly the size of a (slightly flattened) beachball. (The image below is from University College, London.)
(And on the eating of dinosaurs front – remember that not all dinosaurs were the giants of Jurassic Park. They ranged in size from truly enormous down to that of a large domestic fowl. We don't classify an organism as a dinosaur simply on the basis of its size – mosasaurs & plesiosaurs were certainly big enough, but they weren't dinos. And what tells us this? Features of the hip socket – there's a central hole in the hip socket of a dinosaur – and the skull.)
But Beelzebufo certainly was a giant among frogs – about 40cm long & weighing around 4.5kg, with a huge head and gaping mouth. It lived on what's now the island of Madagascar, around 70 million years ago. This is interesting because phylogenetic analyses suggest that its closest relatives are not African frogs but horned toads, previously found only in South America. Frogs, like other amphibians, don't live in salt water, so if the two groups really are close relatives, this suggests that Madagascar and South America must remained part of Gondwanaland at the end of the Cretaceous. If correct, this is an interesting idea, because it reopens discussion of the timing of Gondwanaland's breakup – current models have Madagascar separating from Africa about 160mya – too early for Beelzebufo to have hopped there.
Reference: S.E. Evans, M.E.H. Jones & D.W. Krause (2008) A giant frog with South American affinities from the Late Cretaceous of Madagascar. Proceedings of the National Academy of Sciences (PNAS) 105(8): 2951-2956. doi:10.1073/pnas.0707599105