A codus is a “code virus”. It is like a disease that affects technota. Usually, the codus is a bit of programming code that, when inserted in a technota, commands it to manufacture a particular kind of robot, to dismantle itself, or to alter its behavior in another way. Often, coduses force their host to manufacture the target design only rarely, in order to avoid detection. In other words, a factory will produce a robot secretly, perhaps in the middle of a production run when no other robots are nearby, and the codus will only produce one of its kind, with programming designed to avoid detection. Others will do the same thing to human colonies. For example, a vehicle or appliance might wait until it has certain needed materials and then abscond with them, to manufacture a new robot that will seek human factories to infect with reproductive code. Since many human colonies are unable to make high-tech items like refrigerators, they trade for them en masse, and that means sometimes all of a colony’s refrigerators will coordinate their departure, leaving at once and abandoning the colony without any refrigerators.
Two examples of coduses are pods and assassinbots.
Pods are ubiquitous coduses, present in nearly all robots, that result in destroyed robots’ remains assembling themselves into small pods capable of stealing energy and components and reproducing themselves.
Assassinbots are fiercely devoted to killing humans and to injecting their code into other robots to turn them into human-killers. They are extremely effective at the former but less effective at the latter.