At first it looked mysterious blobs of oil were about to ruin a perfectly good beach day off of the Californian coast. But oil doesn't flee like this.
Huge swarms of anchovies churned near Scripps Pier in La Jolla, Calif., creating undulating swirls of fish that are still as mysterious as they are beautiful.
Check out the video and how the fish flee from the people investigating, only to reform in something like a moving art project.
Researchers aren't sure why the anchovy school was so close to land in shallow waters. It's been 30 years since something similar was spotted. Lucky for us, we have YouTube now.
So rest assured, La Jolla, just when you thought it was safe to go back in the water -- it is, as long as you don't mind sharing it.