A cinematic image of a sinister merman emerging from the shadows of a dark underwater world, his maniacal grin revealing sharp teeth. His humanoid face has captivating yellow eyes that glow with an eerie intensity, contrasting against his human-like skin with a bluish tint. The scene is set with dynamic lighting that highlights his features and casts ominous shadows around his wavy, seaweed-like hair. The background is a murky abyss, adding a touch of melancholy to the merman's sinister allure.