Ancient abyssal sea god monster, towering aquatic aberration with a massive muscular torso covered in dark green scales, crowned with jagged coral-like spines and horn-like protrusions, monstrous face with a wide mouth full of long needle-like teeth, small glowing predatory eyes, thick octopus-like tentacles coiling around its body, barnacles and sea growth on its skin, wet slimy texture, emerging from the depths of a dark ocean, lovecraftian horror creature, highly detailed fantasy illustration, dramatic lighting, dark fantasy style, epic tabletop RPG monster art, painterly style