AMMDI is an open-notebook hypertext writing experiment, authored by Mike Travers aka mtraven. It's a work in progress and some parts are more polished than others. Comments welcome! More.
A variety of group agency. There's a shit-ton of interesting stuff around this word (swarm intelligence, swarm robotics). Modelling swarming behavior is a favorite of artificial life, because a swarm is such an easy-to-grasp model of emergent behavior. A swarm obviously has no central controller; whatever coherence it has as a thing or agent is a function of the behavior of its component individuals.
Boids was an early swarming model done by Craig Reynolds.
Swarming as a mode of conflict
Actually I'm not even sure these things should count as swarms, there is an element of centralized control, which you kind of need in a weapon.
Bruce Sterling Distraction opens with a swarming attack – a crowd of seemingly random people suddenly becomes a mob and strips a shopping center clean (or something like that). And of course he wrote the classic short story Swarm, that one is definitely on the agency required reading list.
Q-anon and the GameStop run both examples of network swarming (Jason Asbahr on FB)