A visitor to my home needed to relieve himself, and he did so on my living room carpet. When I asked him why he did so, he seemed confused. "We always pee on the floor back home in the cave," my troglodyte friend told me. "Helps keep the dust down." I mentioned the smell, and he replied, "Yes, that's sort of a fringe benefit. Makes things smell nice. I just ate some asparagus, so I thought it would really help you out." The stain came out, but it took almost a month for the smell to go away.