A while ago I got an awesome cat tree that provides endless hours of entertainment and joy. One of the most interesting features about my cat tree are several strategically placed balls that are a lot of fun to play with. However, the problem is that the balls are confined to the tree, so you can't just take them to your cat cave or nest. And believe me, I tried for months to pull those hanging balls off - and I've got pretty strong paws! - but with no success.
I hope that helps, although I feel I must warn you that these hanging balls aren't as fun detached as they were on the cat tree *sigh*, so keep that in mind before attempting this irreversible procedure!