Leviathan is a creature mentioned in the Hebrew Bible, and it is described as a large aquatic creature with monstrous ferocity and great power. The Hebrew word for "Leviathan" has the root meaning of "twisted" or "coiled". There are several references to Leviathan in the Old Testament, including in Psalms, the Book of Job, the Book of Isaiah, and the Book of Amos. In Job 41, God describes Leviathan in detail, emphasizing the animals size, strength, and viciousness. The leviathan cannot be tied down or tamed, and it is frightening to even look at. Leviathan is also described as having impenetrable armor and a mouth full of deadly teeth.

Leviathan is often an embodiment of chaos and is threatening to eat the damned after their life. Christian theologians identified Leviathan with the demon of the deadly sin envy. According to Ophite diagrams, the Leviathan encapsulates the space of the material world. Later Jewish sources describe Leviathan as a dragon who lives over the sources of the Deep and who, along with the male land-monster Behemoth, will be served up to the righteous at the end of time.

In Jewish mythology, the name Leviathan can refer to a variety of monstrous creatures, including a primordial sea serpent, a dragon, a snake, a crocodile, or a whale-like animal. It likely developed from pre-biblical Middle Eastern mythology, especially that of the sea monster in the Ugaritic myth of Baal. Leviathan appears in several books of the Hebrew Bible (Old Testament).

In summary, Leviathan is a creature mentioned in the Hebrew Bible, and it is described as a large aquatic creature with monstrous ferocity and great power. It is often an embodiment of chaos and is threatening to eat the damned after their life. In Jewish mythology, the name Leviathan can refer to a variety of monstrous creatures, including a primordial sea serpent, a dragon, a snake, a crocodile, or a whale-like animal.