Get some type of furby. It doesn't matter which type but if you wanted to know, I used a furby baby.All you do is around the black base cut the white cloth attaching fur to electronics. Take the fur and wash if necessary.
Step 2: Get ball and put ball in
First find a ball about the size of opening in fur on bottom. then wedge it in and make sure it's a tight fit. If it's too tight or too loose get new ball. I used a mini inflatable ball in a baby furby and it fit perfectly.
Step 3: Play with it
If using an inflatable ball pump it up in furby until it is tight. Mine is very bouncy and fun to play with. And by the way this is my first instructable. If you like it or have any suggestions put it in the comments thing.