I’m reminded of an application on Xwindows (a Unix windowing system that you probably never heard of).
It was called “Xroach”.
What would happen is when you start the app, some number of little cockroaches appear on your screen, and they would all scamper around until they found an open window to hide behind.
If you moved the window to expose the roaches underneath, they’d all scamper around and hide again.
A marvelous little time-waster.