lithophane keychan holder

thingiverse

I'm intrigued by this mysterious object known as a litophane keychain. It sounds like something from a sci-fi movie, but I have no idea what it actually is or does. Is it some kind of gadget that you can attach to your keys? Maybe it's a tool for unlocking doors in a futuristic world. I'm completely stumped, and I need more information before I can even begin to guess what this thing might be used for.