In case you guys haven't seen this video, it's awesome. It shows a swarm of tiny quadrotor UAVs flying in numerous formations, performing figure eights with each other and even flying around obstacles. Talk about sense and avoid!
The little drones (monsters?) were developed and programmed by researchers at the University of Pennsylvania's General Robotics, Automation, Sensing and Perception (GRASP) lab. The nano-copters were built by KMel robotics, according to the video.
Can't you imagine a swarm of tiny drones like these being launched at an enemy by a small infantry unit? They could be carried in a backpack, controlled by a laptop and sent to spy on a nearby enemy and even explode on any targets they spot, similar to what the Army's Switchblade UAV can do now. They'd be hard to spot until they were on top of the target and given their size and numbers, they'd be damn tough to defend against.
Scary to think about; almost as scary as this.