Here is a cat toy; a hollow sphere containing a few bells and decorated by piercing the walls with cat images.
My daughter's cat likes it although like most cats it happily chases almost any ball. The cat image comes from MaakMijnldee's cookie cutter collection - thing:35495. Other images are included in the openSCAD code.
The sphere has a pentagonal opening; the lid is printed separately and attached with acetone or glue after the bells are placed inside. The bells came from a craft store and are often called "jingle bells". I used the half inch size