This is a demonstration video for a new gadget from DARPA (the Defense Advance Projects Agency), an agency of the Pentagon responsible for coming up with whizzy gizmos like this metal hummingbird. As a commenter on YouTube remarks, although you might think this is just like a remote controlled toy, it's actually an incredibly advanced piece of aeronautical design. Nobody's ever designed a flapping-wing flying machine before, except nature. I'm not quite clear on its raison d'etre, however. Are enemies really going to mistake this for a harmless cute little birdie?