This is a video of toy collector Tim Rowett showing off a plastic wind-up toy that repeatedly transforms from a rolling truck to a walking dog and back again over and over until its used up all its potential energy. My potential energy? It's pretty much zero. I'm just going to lay here with my head on my desk unless somebody offers to take me out for a beer. *waiting* Wow, that was a test and you failed.
Keep going for the video.
Thanks to Yeti, whose only toys are snowballs and broken sticks.