When I first moved to Seattle, I furnished my apartment with everything IKEA for the most part. One of the things I got because I thought it was so cute was a hedgehog air cushion. When we got Darwin, she LOVED this thing. It was just deflated enough that she would climb all over it, and we would push down on a side and she'd roll off and attack it.
We've since gotten rid of it, but for a while it was such an entertaining toy!