Chaoskampf, German for the struggle against chaos, is the scholarly term for the widely attested myth in which a god defeats a monster representing chaos, frequently a serpent or dragon associated with the sea, and thereby establishes or preserves the ordered world. The term entered the field with Hermann Gunkel's Schopfung und Chaos (1895), which identified the pattern in the Hebrew Bible and connected it to Babylonian material.
The instances are numerous and the family resemblance is close. Marduk defeats Tiamat and forms the world from her body. Baal defeats Yam, the sea, and Litan the twisting serpent, in the Ugaritic texts, a find that transformed the study of the biblical material when it was excavated from 1928. Zeus defeats Typhon. Indra kills Vritra, who has penned up the waters, and releases them. Thor fishes for and finally kills Jormungandr. Ra fights Apep nightly beneath the world so that the sun can rise. Susanoo kills the eight-headed serpent Yamata no Orochi. Yu the Great in Chinese tradition subdues the flood, a variation in which the adversary is the water itself and the weapon is engineering.
The Hebrew Bible retains the imagery while subordinating it, and the way it does so is theologically pointed. Leviathan, Rahab and the sea monsters appear as already defeated, or as creatures made for God's amusement: God pierces the fleeing serpent (Isaiah 27:1), crushes the heads of Leviathan and gives him as food (Psalm 74:13-14), and cuts Rahab in pieces (Isaiah 51:9), while Job 41 describes Leviathan at length as a creature no one but God can handle. Genesis 1 uses the vocabulary of the deep, creates the great sea creatures without any combat whatever, and pronounces them good, which many scholars read as a deliberate demythologising of a pattern the writers plainly knew. Revelation returns to the imagery with the dragon and the beast from the sea, and states of the new creation that there was no more sea.
The pattern's persistent function is to make order an achievement rather than a given. Chaos is not merely absent but has been defeated, and may return, which is why the combat is so often re-enacted ritually, and why the monster is frequently bound or confined rather than destroyed. Comparative Indo-European work, notably Calvert Watkins' study of the inherited poetic formula "he slew the serpent", has traced linguistic as well as narrative continuities in part of the material, which strengthens the case for genuine inheritance among the Indo-European instances while leaving the wider distribution unaccounted for.