Tannin

Hebrew mythology presents Tannin as a sea demon who is the epitome of chaos and evil. Tannin (Tanninim, Tunannu) appears in the Hebrew Bible in many places such as:

• Book of Genesis

• Exodus

• Deuteronomy

• Psalms

• Job

• Ezekiel

• Isaiah

• Jeremiah

Tannin was to be created by God on the fifth day, and would later be killed by Jachwe. In Jewish mythology, Tannin is sometimes conflated with the related sea monsters Leviathan and Rahab. In modern scholarship, Tannin is sometimes associated with Tiamat and, in modern Hebrew, the name tannin means crocodile.

While the Tannin of the OT shares much in common with Tunnanu, as known from a handful of Ugaritic texts, we simply cannot be certain to what extent most uses of the Biblical tenn points to a demythol.

Canaanite mythology

Tannin appears in the Baal Cycle as one of the servants of Yam (lit. “Sea”) defeated by Baʿal (lit. “Lord”) or bound by his sister, ʿAnat. He is usually depicted as serpentine, possibly with a double tail.

Source:

Dictionary-of-Deities-and-Demons-in-the-Bible

en.wikipedia.org/wiki/Tannin_(monster)