Marina couldn't take her eyes off of her new pectoral fins. She flexed them, curled them as if trying to grip something, then looked up to the surface. It wasn't like she needed to take a breath quite yet. And besides… she couldn't deny that she wanted to just… swim.
Her body was changing, like it wanted her to swim. She could feel it, internally, she was changing, as well as the compulsion to go further out, further down, to find her limits.
With a powerful kick of her tailfin, she was off, racing through the dark water. Schools of shimmering fish darted out of her way, and she turned swiftly after them. Something drove her to swim after them, not quite hunger, but an urge like it. Her tongue ran over her teeth, which were growing sharper and bigger, her mouth widened. The change was steady, as was the stretching of her lips. She opened her jaws, salty water rushing inside of her mouth and down her throat as she chomped at a fish.
Bubbles expelled from her sides as gills opened, the water filtering through them. She no longer needed to breathe air, and that meant she could dive deeper, right?
She stopped as she noticed the change. Her chest still expanded to take in water through her nostrils, and it was expelled through the gills at her sides. Marina looked up at the bubbles as the floated up to the surface.
The surface.
She couldn't leave the water now that she was breathing water.
Her face darkened, the material that had become her skin was now creeping over the only bit of pink human skin that remained. It crawled up her chin and the back of her head, her hair falling away. She looked around herself as her hair slowly sank past her. Marina curled her head forward, and ran a fin over the back of her head. Smooth, almost spongy, like the rest of her skin.
Her nose sank back, nostrils becoming mere slits on her face to allow for water to flow into her system more easily. She felt the urge to swim again, staying still like this made her feel… well, like she wasn't breathing, which wasn't good. She took off again, swimming down deep towards the darker ocean. That felt better.
As her neoprene skin subsumed the rest of her face, it finally reached her eyes, which darkened and grew larger. Her range of vision expanded, as did her pupils, allowing her to take in far more light than before. Then, she felt the muscles in her neck stretch, and found it far easier to keep her head looking straight ahead, keeping in-line with the rest of her body.
Yet, as she dove deeper and deeper, she knew she wasn't quite… complete. The amulet glowed a dim blue color, as it fused itself to her chest. It was a strange sensation, but it felt empowering. Marina continued to swim deeper and deeper, as the water grew colder and darker.
She was well beyond the point of no return now, and was perfectly fine with that.