This is a ball toy for your cat. Cut out the four ribs at the bottom and the internal parts will be free to move. Scale up the model according to your cat's size. A scale coefficient of 1.5 was enough for my cat Pisana. This model also shows the possibilities of 3d printing.
https://grabcad.com/library/cat-ball-toy-1
If you don't receive the email within an hour (and you've checked your Spam folder), email us as confirmation@grabcad.com