Tim has an amazing funhouse of a brain. And several years ago, at a pool party, he pulled a rake and green U-Haul pallet wrap out of his car, took the rake part off the handle, and then attached the rake to his feet with the pallet wrap and called himself a mermaid.
(Reader, I married him.)
This has only escalated in the years since. We have friends who have a pool party 2-3 times during the summer, and, knowing this, Tim could plan ahead to make his mer-tail faster, better, stronger. The one in the picture is from last year, and that was version 4.
Just now, I had to ask him what it was made of, because I honestly had no idea. It's basically electrical tape, but 8-inch wide electrical tape from an industrial electrical contractor. The fin was made of more of the tape, but shaped with plastic strips that held litho plates onto a printer. (This was all scrap that came into his work. He believes very strongly in reduce, reuse, recycle, even when it comes to swimming pool shenanigans.)
So this is last year's pool party. The host has an underwater camera, and the rest is history.