We built them to learn: intelligent, fast, mobile, independent and reliable. The Microbots were incredibly efficient in the fields, saving millions of dollars of crops, eradicating pests wherever they saw them and learning new ways to hunt in groups or swarms, even using their own mass to smother entire colonies of crop destroying pests. 

But we hadn't envisaged that they would learn to reproduce, to build, to consider themselves in competition with us for the planet on which they depended for materials to build more of their kind. The Swarm was born, and suddenly we were fighting a new war...

A drabble, exactly 100 words based on a prompt from Challenge Corner for #Wattpadwednesday