Great advice, Beth Andrea. After anibioman suggested the easter eggs, I thought about using the miniature ones as a mold. We may have a few from my childhood somewhere, but I can't remember how big/small they are.
The packer itself isn't actually silicone. It's made of "Real Feel Superskin", a porous "cyberskin"-like material. I'm not looking for movement as much as feel.
Once Easter comes around, it'll give me an excuse to snoop around for the old eggs for a mold. I'd rather not explain why I want to see them now lol