The term "Leviathan" refers to a very large, extinct animal mentioned in the earliest writings of the Old Testament, the books of Job, Psalms, and Isaiah.
* Leviathan is described as a large, snake-like creature, strong and fierce and able to make the water around it "boil." The descriptions of it were similar to that of a dinosaur.
* Isaiah the prophet refered to Leviathan as "the gliding serpent".
* Job wrote from firsthand knowledge of Leviathan, so the animal was most likely alive during his lifetime.