I remember when I was younger I had a book I absolutely loved. It had a bunch of interchangeable monsters. When you turned part of a page, the head or torso or legs of the monster would change into a different part of a monster. I love this idea from Meaningful Mama. She made interchangeable kid blocks. They can change themselves or even mix with the other kids blocks in the family for some really funny looks! My kids would love these!
See the interchangeable kid blocks.