Spiky, knee-high nocturnal 'Roomba' mobs that clear corpses and refuse — deadly only if you're in their way.
Street Urchins are the Over City's janitor mobs — level-8, knee-high, spike-covered creatures that roll like tumbleweeds and come out only at night to remove dead bodies and refuse (the ruins' version of a Roomba). Once pampered pets of the rich, transformed by the cataclysm into larger, deadlier, spikier scavengers, they won't bother anyone who doesn't get in their way. A swarm besieged Mongo and the sleeping Princess Donut — not out of aggression, but to reach the wood-and-metal defensive pile Carl had stacked around Donut — skewering both with fifteen-inch black spikes until Carl removed the debris into his inventory and they lost interest.
Squat, black, knee-high creatures covered in long (~15-inch) black spikes, moving in rolling tumbleweed fashion; only active at night.
The floor's night-only cleanup mobs — a hazard only when blocking their work.