Killing Cloud

This thing doesn't have a solid body. It's a glittering mass of barely visible, insect-like robots with razor-sharp points. A killing cloud is a construct, or more accurately a swarm of constructs. Each individual component of a killing cloud is a small microdrone about the size of a honeybee, an aerodynamic teardrop propelled by tiny thrust jets. Each drone bears a razor-sharp edge along its surface, and has a microcomputer linking it to the rest of the swarm. The swarm acts as a unit, communicating with each subunit with coded radio signals. Killing clouds originated as defense mechanisms, swarms of controlled drones that patrolled sensitive locations like bunkers and command centers. Now their controllers are long dead, and the corrupted programming of the surviving cloud swarms leaves them with little to do than patrol empty complexes or roll slowly through the wilderness. If a killing cloud happens upon a human settlement, it may turn aside in compliance with Ancient safety routines, but it’s much more likely to classify all within as intruders and attempt to neutralize anything moving.