As a kid, I was totally into transformers. I didn't have too many of them to play with (just a couple), but I watched many episodes of the cartoon, wished to get something Transformer-related for christmas and all that.
And even though I don't care about the toys anymore (or even the 2007 Transformer-movie, for that matter), but I still really enjoy the idea of something being one, and being two different things at the same time. A transformer might be a car - looking a bit odd for a car, though - and when transformed into a robot, it still has a slight car-like appearance. The two identities are merged into one, with the one slightly influencing the other.
That being said: some transformers move beyond that, and contain a little surprise. Like these sneakers. They are sold by Nike, are packed in a typical shoe-box, and look exactly like a pair of sneakers. But it is impossible to wear the shoes, since they are actually toys: a transformer is hidden inside the shoe. The toy is hidden in the shoe, making it quite a surprise discovery when the robot pops out. If I were a collector of either shoes or transformers, I'd love to get one of those. But since I'm neither of the above, I'll just stick by saying that these transformer-shoes are absolutly lovely.
I found these shoes/transformers via designboom.com, by the way.