The Leviathan was a mythical sea monster that is mentioned in the Bible that creationists believe to have been a real animal. Most creationists claim that the Leviathan was a Sarcosuchus, a species of giant crocodile that did in fact exist, but died out in the K-T mass extinction. Some creationists believe Leviathan could have been a dinosaur, such as a Parasaurolophus or Corythosaurus, or a plesiosaur such as Koronosaurus.
One main trait of the supposed Leviathan was that it could breathe out fire. Amazingly, creationists have started to suggest that Sarcosuchus and even the hadrosaur parasaurolophus could breathe fire!
 Couldn't be true
Leviathan could conceivably have been an aquatic dinosaur such as a liopleurodon; however, in the Book of Psalms, Leviathan is described as having seven heads. No animal has seven heads.[citation NOT needed]
As for the fire-breathing argument presented by creationists, if dinosaurs could breathe fire, they would have had adaptations around their mouths to protect their mouth and throat from flame. Nothing resembling such an adaptation has ever been seen. Another question is what use an aquatic sarchosuchus would have for breathing fire; it would have to be concluded that God gave them this purpose in anticipation that millennia later, a few cranks would use it as proof that the Bible is true in all particulars.
 In religion
The Leviathan is equated with the Sin of Envy; however, it is also described as being king over all the sons of Pride. As such, some Biblical scholars argue that the Leviathan is a metaphor for Satan.
In the Book of Job, God is described as having "crushed the heads of the Leviathan" and in the Book of Relevation, it is stated that the Leviathan will be served as the main course at a banquet for the righteous. Let's just hope "the righteous" like seafood.