Leviathan

The Leviathan was a gigantic aquatic animal that could breath fire described in the book of Job.

A Crocodile?
Hebrew text, he has ‘terrifying’ teeth and scales like rows of shields, closely fastened together and hard as stone. He is a resident of the sea, knowing no fear and apparently immune to all man’s weapons.

Many scholars identify this animal as a crocodile, but as other experts have pointed out, there are several problems with this idea.

Although some crocodiles do venture into the coastal areas and can swim out to sea, the deep ocean is not their normal habitat. They are found mainly in inland waters, where they live in lakes, rivers, swamps and estuaries, and breed on the shores. Therefore they would not be described as great beasts of the sea. Nor are crocodiles so terrifying that no one dares tackle them—crocodiles are regularly trapped and killed by native tribes with simple technology.Job also says that Leviathan could "Shoot burning sparks and hot coal out it's mouth". Do you Know of any living creature that breathes fire?

So, what was Leviathan?
Leviathan could have been a kronosaurus, like the picture.We don't  know if it could breath fire, just like if we found a fossil skunk we couldn't tell by the bones that it could eject a horrible smell.Plus, the bombadeir beetle can shoot sparks, so we know animals are capable of that sort of thing.Leviathan could also be a sarchasuchus, witch is a GIGANTIC extinct crocodile.Sarchasuchus had a strange hole in the back of it's mouth, and scientists don't know what it's for.It could be to help it breath fire.