The video below was released by the Air Vehicles Directorate, a branch of the US Airforce, to promote the concept of swarms of small drones released into an urban environment to conduct surveillance and assassination missions. Other than the ornithopter manner of the drones hovering and darting through restricted airspace, there isn't much here that hasn't been seen in other drone models. What really makes this striking is to see all of these elements, the remote monitoring, the use of man-made power sources such as power lines, the visual navigation systems and lethal payloads, placed into something small and ubiquitous.
Present drone technology has essentially produced remotely piloted airplanes, small and relatively expendable, but not that many steps removed from a piloted airplane. But the notion of militarized swarms hiding in plain sight, living off of existing power systems to me seems a very radical notion, and one I haven't really seen fully explored in speculative fiction. What if the near future produces an urban ecosystem with the usual biological species rubbing shoulders with a myriad of cybernetic constructs. Like an ecosystem, this complicated web of relationships between the plastic and metal animals and the more traditional rats, pigeons and humans would include competition, cooperation, parasitism, and predation.