Crowd Chaos is all about giving separate interests to a large number of NPCs, so they look like they are living their own lives. In its lightest form, this can be something very simple, such as a whole bunch of NPCs picking random targets, walking to them, possibly sitting still for a moment, and then starting over. This stands out in real-time strategy games when buildings are constructed, and you see a construction worker walking to random points of the structure and waving their arms about.
Every game that needs crowd chaos will typically have a basic wandering base, and it can be extended as needed. Perhaps the crowd will form lines of more NPCs that are waiting at a spot. Perhaps the targets have changing values and AIs prefer higher values. They pick up a random block and put it somewhere else. The base wandering behavior needed for these and other crowd behaviors is what we will implement in both React and RAIN AI.
