[kooshball]

It can get smaller.

> As a result, hazardous elements such as the assemblers, the bacteria, and the nanobots were blown into the desert, evolving and eventually forming autonomous swarms. These swarms appear to be solar-powered and self-sufficient, reproducing and evolving rapidly. The swarms exhibit predatory behavior, attacking and killing animals in the wild, using code that Jack himself worked on. Most alarmingly, the swarms seem to possess rudimentary intelligence, the ability to quickly learn and to innovate. The swarms tend to wander around the fab plant during the day but quickly leave when strong winds blow or night falls.

http://en.wikipedia.org/wiki/Prey_(novel)