This is pretty great!
Pro-tip: You can run the app a couple times to spawn more geese, but each goose added eats up more CPU (on my computer, each goose was eating 20% CPU usage). Maybe optimize this?
I've also noticed on a multi-monitor setup, the goose appears only on the main screen. It can travel to the other monitors if it is chasing your mouse, but you can't see it on the other monitor.
This is really neat and I hope to see more updates!