A dramatic, high-contrast digital painting suitable for a thriller audiobook cover. The central image depicts a colossal, ancient stone cyclops eye peering ominously from the crushing depths of a dark, turbulent ocean. Hints of a sunken, colossal structure are visible behind the eye, suggesting a lost civilization or a hidden threat. Rays of moonlight or a faint underwater luminescence pierce the murky water, illuminating swirling debris and the texture of aged stone. The overall mood is mysterious, powerful, and slightly unsettling, with a color palette dominated by deep indigos, dark teals, murky greens, and stark, pale whites for highlights. The composition is powerful and focused, with the cyclops eye as the undeniable focal point, evoking a sense of immense scale and unseen danger. The image should be rendered in a square 1024x1024 format, with a professional, cinematic quality, emphasizing depth and atmosphere without any textual elements.