[ccsnags]

In the book “The Diamond Age” by Neal Stephenson there are mist-like swarms of nanobots that act as an immune system for regions against malicious nanobots.

I can picture there being something like this with drones.

There are problems to this. The major one being that, as mentioned by the posts on this thread, you have to develop the weapon to really know how to counter it.

[_jal]

That's the Extropian "Utility Fog" concept.

A more direct science fiction forerunner of this is Bruce Stirling's _Islands in the Net_ (1988). There is a scene where cheap explosive drone swarms are used in terror attacks.

And of course, there's the famous first line of _Count Zero_.

"They sent a Slamhound on Turner's trail in New Delhi, slotted it to his pheromones and the color of his hair. It caught up with him on a street called Chandni Chauk and came scrambling for his rented BMW - Its core was a kilogram of recrystallized hexogene and flaked TNT."