Tannin appears in the Baal Cycle as one of the servants of Yam (lit.'Sea') defeated by Baʿal (lit.'Lord')[3] or bound by his sister, Anat.[4] He is usually depicted as serpentine, possibly with a double tail.[4]
The word Tannin is used in the Hebrew Bible fourteen times. Aaron's staff becomes Tannin in the Book of Exodus (Exodus 7:9-12), it is used in the meaning "snake" in the Book of Deuteronomy (Deut 32:33) and Psalms (Psalm 91:13). It represents Nebuchadnezzar II (the king of Babylon) in Jeremiah (Jeremiah 51:34) and Pharaoh in Ezekiel (Ezekiel 29:3, 32:2). In the Book of Job (Job 7:12) the protagonist questions God "Am I the sea or the sea dragon that you have set a guard over me?"[20]
^This passage in Isaiah directly parallels another from the earlier Baal Cycle. The Hebrew passage describing the tannin takes the place of a Ugaritic one describing "the encircler"[17] or "the mighty one with seven heads" (šlyṭ d.šbʿt rašm).[18] In both the Ugaritic and Hebrew texts, it is debatable whether three figures are being described or whether the others are epithets of Lotan or Leviathan.