Transformation in art works with physical form, and greatly relies upon the materiel with which it is made of.  In light of that, I think I found the coolest example out there (in my opinion); Bumblebee from Transformers made entirely out of recycled material!  This goes to show that you can make something incredible, like a high-tech-looking robot from outer space out what was once essentially trash.  Below is the piece referenced.  :D