During the final stage of the Last Age of Man alternative food sources became imperative. The top-side of earth was inhospitable to most any agriculture and other planets had yet to be terraformed enough to be able to create food to feed the world.

So man sent robots underground and started fungus farms. This worked well for a while. The P-SILO68N unit was developed to cultivate and harvest fungus that would then be processed into food pellets fit for human consumption. The fungus itself however is intelligent and has meshed with the circuitry of the robots that harvest it, creating a symbiotic relationship between fungus and machine.