(host) It's 70 million years ago and you are in northwestern Madagascar.

The climate is subtropical and very seasonal with long periods of drought broken up by stretches of heavy rain.

Rivers dry up, leaving only ephemeral pools behind.

It's a hard place to live for you and even your average amphibian.

But this place is home to one hell of a weird frog.

Paleontologists call it Beelzebufo , the so-called devil frog.

And it may have been the largest frog that ever lived.

Beelzebufo thrived in this environment possibly because of adaptations that it had in common with some modern frogs that still live in these kinds of habitats.

For one thing, his proportions were just weird because it had a disproportionately big head and a really wide mouth.

And it probably had an incredibly powerful bite, making it a serious predator for smaller animals.

It also had these flanges of bone on the back corners of its skull that were so big that they may have overlapped with its shoulder blades, and even affected the movement of its arms.

Now, the thing is, there are frogs around today that look a lot like this with big bumpy skulls and huge mouths.

And you want to know what they're called?

'Cause it's really awesome.

When scientists are trying to be all serious about them, they referred to these modern frogs as ceratophryids.

But they're more commonly known as--wait for it-- Pac-Man frogs.

And phylogenetic studies group Beelzebufo with modern Pac-Man frogs.

But here's the problem.

Pac-Man frogs only live in South America and Beelzebufo is only known from Madagascar around 70 million years ago, and Madagascar and South America haven't been connected for like 115 million years.

So if these frogs are related, paleontologists have to explain how they ended up in totally separate places and figure out where and when their ancestors lived.

And if it turns out that they aren't related, then why do they look so similar?

Untangling the origins of Beelzebufo , the giant frog that lived alongside the dinosaurs, turns out to be one of the most bedeviling problems in the history of amphibians.

The first fossils of Beelzebufo were collected in 1993 in the Mahajanga Basin of Madagascar, and more bits and pieces were found each field season after that.

But this odd frog wasn't fully described until 2008, once there was enough of it to compare it to other living and extinct frogs.

And that comparison to living frogs is where the trouble started.

Even before the discovery of a partial cranium in 2010, it was clear that Beelzebufo really looked like a Pac-Man frog that had somehow ended up on the wrong continent.

And the devil frog also turned out to be just really big.

The biggest modern frogs live in Africa and are known as Goliath frogs.

These chunky boys can get up to just over 30 centimeters long and weigh more than three kilograms.

But the largest estimates put Beelzebufo around 40 centimeters long and 4 12/2 kilograms.

And based on its features, we can get at least some insights into what its ancient habitat was like, and maybe even its behavior.

For example, based on its limb proportions, the devil frog probably walked on land rather than hopping from tree to tree like some frogs do, and his big blobby shape and short limbs would have helped keep it from drying out as quickly as a smaller frog would have.

It also may have been a burrower using its back legs to dig into the soil and make a nice cool place to hang out during the hottest and driest parts of the year.

This is something that frogs and toads still do if they live in seasonal environments.

But where things start to get weird is its head.

Beelzebufo had what's called a hyperossified cranium, meaning that it had extra bone tissue that formed a series of pits and ridges over most of its skull, giving it a bumpy texture.

It also had an extremely wide mouth and was probably capable of biting really hard.

In a study published in 2017, researchers measured the bite forces of living Pac-Man frogs, then scaled those measurements up to estimate the bite force of Beelzebufo.

And they found that the devil frog may have had a bite as strong as a snapping turtle with a similar head size, and pound for pound could even have rivaled that of a lion or a tiger.

Living frogs with morphologies like Beelzebufo tend to be aggressive ambush predators.

So the devil frog probably was one too.

Its powerful bite may even have allowed it to prey on small crocodilians or even juvenile dinosaurs.

A frog that hunted baby dinosaurs?

It's possible because several dinosaur species have been found in the same formation where Beelzebufo was found.

Okay, but so all of this weirdness aside, the thing that really perplexes us about this frog is where exactly it came from.

The key question is, did Beelzebufo just look like a Pac-Man frog, or was it actually related to them?

Pac-Man frogs live in places a lot like where Beelzebufo lived-- in warm, arid habitats with pools of water that dry up seasonally, and modern Pac-Man frogs and Ms. Pac-Man frogs are also large predators with hyperossified skulls.

Now it's possible that this is a case of convergent evolution, where species with similar lifestyles develop similar adaptations, in this case, giant mouths and body shapes and sizes that allow them to survive dry spells.

But if they are actually related, well, we have a problem because then we have to explain how Beelzebufo ended up only in Madagascar while Pac-Man frogs are found only in South America.

In order for the ancestors of Beelzebufo and Pac-Man frogs to spread to both places, there would have to have been a connection between Madagascar and South America by way of Antarctica.

But we now know that Madagascar was fully separated from Antarctica by around 115 million to 112 million years ago.

So this means that the group of frogs that was ancestral to Pac-Man frogs had to, first, evolve into its own distinct group, and then migrate to Madagascar before 112 million years ago, assuming they got there by land.

But so far, the science says that just wasn't the case.

Molecular clock studies suggest that at the earliest, those ancestors of Pac-Man frogs didn't evolve until 88 million years ago, long after Madagascar had already broken away.

Now the fossil record may provide some evidence that this group originated earlier, but the record is still really spotty.

So the timing just doesn't work for these ancestors of Pac-Man frogs to get to Madagascar by land.

Okay, but what about rafting?

We know other animal groups made it to the island by riding on random naturally formed rafts of plant material.

So could the ancestors of this giant scary frog have done the same thing?

Well, even if they did get to Madagascar after it split off by rafting, the molecular clock estimates for when Pac-Man frogs originated are still too recent.

Their origin is generally estimated at some time after 65 million years ago, which is 5 million years after Beelzebufo was already terrorizing Madagascar.

So there's a lot about this frog that science can't quite explain yet.

We're not sure where it came from, and we're not sure where it went.

All of the fossils that we found of it come from sites dated to the Late Cretaceous, and there are no frogs closely related to it on Madagascar today.

So it's possible that Beelzebufo went extinct during the extinction event at the end of the Cretaceous period.

But we can't know for sure until we find more sites and more fossils that are more recent than that.

Now, even though we don't have a lot of answers, this weird amphibian can still teach us a lot about the patterns of evolution.

Like, if Beelzebufo and Pac-Man frogs aren't related, and they just converged on the same adaptations, then that tells us that there's something about being big and mean and extra bumpy that gives a frog a selective advantage in a dry seasonal environment.

And if they are actually related, then that tells us that there may be gaps in the fossil record of frogs that's used to set the molecular clock and that frogs were probably much more widespread back then than we thought.

But hey, if nothing else, you and I learned today that Pac-Man frogs are a thing, and that makes me pretty happy.

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