What is a common characteristic of mythical sea creatures?

A common characteristic of mythical sea creatures is their origins in folklore. Throughout various cultures, these beings often emerge from the tales and stories passed down through generations, reflecting the human experience, beliefs, and the mysteries associated with the sea. Myths serve to explain natural phenomena, embody moral teachings, or even entertain, making the folklore aspect pivotal to the existence of these creatures.

In contrast, while some mythical sea creatures may play specific ecological roles, this is not a defining characteristic across all legends, as many are purely fictional and not tied to real-world ecosystems. Similarly, the physical size of these creatures can vary widely from culture to culture, so it does not form a cohesive characteristic that defines them universally. Lastly, their relationship to humans can be complex, with some tales depicting them as benevolent and others as dangerous, yet this relationship is more of a narrative device and less of a foundational element compared to their folkloric origins.