A stunning yet eerie mermaid emerges from the depths of a fog-covered lake, her scales glistening with a wet sheen in the dim, dramatic lighting. Her eyes, captivating and sinister, peer through the mist, a siren of ancient and unholy allure with an intricate and hauntingly detailed design. The atmosphere is dense with mystery, casting shadows that dance around her ethereal form, evoking a sense of horror and wonder. The scene is captured in a photorealistic and cinematic style, rendered in 8k, emphasizing the unsettling beauty of this dark aquatic enchantress.