Transformers are real. At least, in any event, six-inch-wide transformers made out of paper, plastic, and nine volt batteries:
This self-assembling, origami-inspired robot is the creation of engineers from Harvard and MIT, and was revealed in a study published today in Science. It transforms when its circuit is turned on, delivering heat to various spots in the robots' joints, which causes the memory plastic to fold, lifting it up from the ground over the course of about for minutes (it's been sped up in the GIF above). Two motors then allow it to scuttle away on four legs at a speed of around 500 feet per hour.
The engineers made the robot with an algorithm that could be used to create a variety of complex 3D objects from a flat material. With it, they say, we could design robots to be shipped out to all sorts of situations in a flat, packable shape, then get up on their own and do useful things — say, collect environmental data, or map a remote comet.
Optimus Prime, alas, still appears to be several years away.