Inspired by this article: https://what-if.xkcd.com/25/ Bot Season happens every so often; a group of robots of strictly of sub-AI intellect gathers and wanders, together, in a migratory pattern throughout the city, or maybe even across the surface of a planet – the phenomenon is most well documented on Mars, where there is a high population of humans and resultant high bot population, but it can occur even inside dome cities, just to a much smaller extent. The mob of bots is usually comprised of simple artificials; ownerless creepies, children’s toys, DIY educational kit robots, cleaning and gardening bots, LAI-guided automechs, building maintenance drones, sometimes even free-floating microswarms; that sort of thing. The one thing they all have in common, besides poor programming, is a solar cell and a light sensor. To understand why Bot Season happens, you have to understand that many bots are programmed to seek out solar sources to recharge their batteries before starting their assigned tasks. Poor programming might mean they ignore the boundaries set by their owner; a defective battery might mean they are always seeking the sun, never able to store more power than their short-term capacitors allow, never reaching that critical “IF [battery]==[full] GO TO [run_task]”. They see the sun in the sky, they move towards it. When the sun rises, they wander east, following the easiest navigable route. At noon they are stationary, or climb the highest structure around. In the afternoon they wander west. At night, they lose power, wherever they end up, ready to seek the sun in the morning. All the time they are in motion, they are wandering a couple of kilometres per day towards the solar equator, the closest point on the planet to the sun. Travelling in zig-zagging waves, some eventually reach this point, or an area close to it. They end up next to other bots. And in the morning, they move together, driving or crawling or hopping their way towards the sun. Inside dome cities, they usually end up just going back and forth at one end of the dome or do annual laps if it’s close to the equator, until they’re eventually collected and recycled by civic authorities or trashed by hooligans or reclaimed by their owners. And very rarely, these mobs take on a life of their own; in proximity to other bots of different types, some might send automatic requests for maintenance. A repair bot in the mob responds, fixing a tread. Its requests for fabber feedstock are answered by rubbish-collectors, who tip their catchers into its fabber. They don’t always work in harmony, but when they do, it’s almost like they were designed for it. When the mob rolls into town again, it’s Bot Season, maybe causing a few traffic hold-ups, but usually an entertaining distraction for the folk that live and work there. A-Life fanatics can sometimes be found blogging on these mobs, sometimes even instigating them; releasing tagged bots made from spare parts into "the wild" to join the mob. The only problem is, of course, that on Mars, their rambling, scattered course around the equator takes them right into the TQZ, and then right out again.