The DelFly Micro is an image sensing mini-dragonfly that weighs a mere 3 grams (0.000472419133 stone) . You can fly it manually or transmit video back to a PC which then moves the wee one through the air autonomously.
This thing has become smaller and smaller over the years and now it’s a little bigger than a Euro coin. You sadly can’t buy this thing, but expect them to be in the first wave of war machines when the robots rise against us.