What is a evil marine spirit?

An evil marine spirit is often depicted in folklore and mythology as a malevolent entity associated with the sea, such as a sea monster, mermaid, or water spirit. These spirits are typically believed to possess the power to lure sailors to their doom, cause storms, or bring misfortune. In various cultures, they symbolize the dangers of the ocean and the unknown, embodying fears of the natural world's unpredictability and peril. Their narratives often serve as cautionary tales about respect for nature and the consequences of hubris.