mermaid, Neptune's shell, sitting on rock, (18yo), long flowing hair, seafoam green scales, shimmering tail, pearl necklace, starfish accessories, holding trident, ocean background, coral reef, colorful fish, underwater, soft light filtering through water, bubbles, dynamic pose, 3/4 view, detailed texture, vibrant colors, fantasy, ethereal beauty, sunken treasure, marine life, wide-angle lens, high-resolution.