Wikipedia
In Mesopotamian myth Labbu was a lion-serpent sea-dragon, that was killed by the god-king Tishpak, "warrior of the gods". The myth recounting the predations and defeat of this supernatural adversary figure, of which the most familiar is Satan, has Canaanite origins; it appears in two very fragmentary cuneiform texts: one is in Old Babylonian; the other, much later, in Assyrian, was discovered in the library of Ashurbanipal (CT 13.33, 34). The opening of the Old Babylonian version recalls that of Gilgamesh:
The cities sigh, the people...
The people decreased in number,...
For their lamentation there was none to...
The vast dimensions of Labbu are described. The sea, tāmtu has given birth to the dragon (line 6). The fragmentary line "He raises his tail..." identified him for Neil Forsyth as a precursor of a later Adversary, the dragon of Revelation 12:4, whose tail swept down a third of the stars of heaven, and cast them to the earth.
According to the fragments, " Enlil drew [a picture of] the dragon in the sky"; whether this refers to the Milky Way (Heidel 1963) or a comet (Forsyth 1989) is not clear. The pantheon of Babylonian gods are terrified by this apparition and appeal to the sun-god Sin: who will slay the dragon and exercise kingship? Though he is not explicitly identified in the fragments, it is Tishpak, the protector-god of Eshnunna, who is appointed as hero. Amidst the storm he creates, bursting open the clouds, he dispatches Labbu with an arrow.
The epic fragments are not part of a cosmogony, Forsyth notes, as the cities of men already exist. F.A.M. Wiggerman found the myth's function as justifying Tishpak's accession as king, "as a consequence of his 'liberation' of the nation, sanctioned by the decision of a divine council."