Good: double amputee gets prosthetic legs so she can walk. Better: double amputee gets realistic-looking mermaid tail so she can swim. Awesome: it's developed and built by Weta, the special-effects company that did work for the "Lord of the Rings" movies, as well as "King Kong" and "The Chronicles of Narnia" series.
Nadya Vessey's legs were amputated below the knee when she was a child due to illness. At one point, reports Stuff, a child asked her what happened to her legs and she told him she was a mermaid. The idea stuck with her, so she wrote to Weta Workshop in Wellington, New Zealand, two years ago asking for a mermaid tail. To her surprise, they said they'd do it.
Now she has a fully functional mermaid tail with an attached suit, making her look practically just like a real mermaid (if, you know, mermaids were real).
She can swim well and says the prosthesis feels quite comfortable. We're not sure if anything like this could go into mass production for amputees, but we wouldn't be surprised if 10 years from now there are mermaids swimming about in your local pool.