Bašmu

In Mesopotamian mythic accounts Bašmu is described as a creature 'created in the sea' and as one of the monstrous brood generated in primeval contexts. It is enumerated among Tiamat's creations in the Enuma Elish and appears in narrative lists of foes overcome by a divine warrior (for example the Angim / 'Ninurta's return to Nippur'). These attestations place Bašmu in the corpus of sea-born, chthonic monsters opposed to the younger gods.

Descriptions and iconographic notes in the surviving summaries portray Bašmu as a large venomous snake with horns; some depictions or correlated Sumerian terms indicate additional appendages such as two forelegs and wings. A fragmentary Assyrian myth gives an extraordinary measure for its length ('sixty double-miles long'), and a fragmentary Enuma Elish passage attributes to it 'six mouths, seven tongues and seven ...-s on its belly' (textually fragmentary and uncertain). Related Sumerian terms (ušum, portrayed with feet, and muš-šà-tùr, 'birth goddess snake', portrayed without feet) may reflect variant iconographies in the same conceptual field rather than a single fixed depiction.

Textual summaries attribute prodigious size, voracious appetite, and destructive behavior to Bašmu: an Assyrian fragment states it devoured fish, birds, wild asses, and men. As one of Tiamat's host in the Enuma Elish it functions as part of the cosmological threat arrayed against the gods. The name is also used as the Akkadian designation of the Babylonian constellation MUL.DINGIR.MUŠ (identified with the Greek Hydra), a scholarly identification of an astral label rather than an attested technical astromagical power in the supplied sources.