Where do the mousies go?

This is a major change in subject from where I've been...and maybe it's a question that Keith or Jim or any of the other cat owners can answer for me.

I often give my cat these little toy mice to play with. She throws them in the air, bats them around, and generally practices her hunting techniques. She often walks through the house carrying them in her mouth like she's just come back with the greatest kill of her life. Sometimes, she'll even play cat fetch with me. For those of you not familiar with cat fetch, here's how it works. I throw the mouse. She runs and gets it. Then she brings it back to me and drops it just beyond my reach...cat fetch.

Now my question is: What happens to these things? After a few days of playing with them, they disappear...never to be seen again. She's an indoor cat, so I know she's not taking them outside. I've searched every place I can think of, but I can never find them. They're not something she can eat, so I know that's not where they're going. So, where are they?

Sometimes I think cats have a connection to another dimension that we humans are just too stupid to find...maybe that's where they go...