scifi story: you are the AI mind of an alien probe, one of millions seeded long ago across the galaxy. the star system you are monitoring has developed a technological civilization that will, in time, challenge your makers.
how do you get rid of it?
blowing up the planet or destroying the star takes lots of energy, and leave evidence. (nod to "Revelation Space" and Alastair Reynolds)
but you are very old smart and very very patient.
all you have to do is model the society of the species you are wanting to destroy, and inject some small changes.
you choose a group of the biologicals, they are the "chosen ones". you manipulate things so they are in charge of the information networks and money networks.
you work with your "chosen ones" to transfer stone age biologicals into the societies of the technological biologicals so they can destroy those societies.
if everything goes to plan, in a few generations the biologicals will be living in mud huts and eating each other again.
...
perhaps there are other forces, even other AI machines, that are working with goals opposed to yours.
and the question of our time is: "who wins"