The creature representing chaos and storms in ancient Mesopotamian mythology is Tiamat. She is often depicted as a primordial goddess associated with the saltwater ocean and chaos, embodying the power of creation and destruction. Tiamat's battles against the younger gods, particularly Marduk, highlight the struggle between order and chaos, forming a foundational narrative in the Enuma Elish, the Babylonian creation epic. Her legacy reflects the dualities inherent in nature and mythology.