The creature from mythology depicted as a serpent-like being associated with water bodies is a serpent or dragon, often referred to in various cultures as a water dragon or serpent deity. Examples include Numskull in Native American lore and Yamato no Orochi in Japanese tales. These creatures commonly symbolize power and fertility, representing the life-giving aspects of water. Their connection to water bodies makes them significant in religious and cultural narratives, emphasizing the reverence for natural elements.