No doubt a happy accident!
I went adventure driving while on my way to a job, and the waves at Pacifica were very pleasantly large– apparently just past the peak of high tide for the day. I spent a bit of time capturing frames on my iPhone, and then came across burst mode, which I had never put to use before.
After a bit I thought, "I should get the obligatory selfie of this adventure!" So I flipped to the selfie cam and hit the button. Of course, the camera was still in burst mode, so I got a bunch of nearly identical frames. It did occur to me that Google Photos might make something of them, and sure enough, here I am sitting still with the background moving behind me. Cool!