i was wandering around foraging with one eye on the mini-map and the other on the game looking for good things to find and bad things to avoid, when a big (at least 4x the size of the red X that designates my position) brown ball appeared on the mini-map. It had fuzzy edges an was moving around quickly. I approached it, and in game it was a fairly smooth-looking brown ball moving much faster than I could rolling around somewhat erratically.
Have I just encountered a URO (Unidentified Rolling Object)?
Any ideas as to what it might be?