Mushrooms

At first, the mushrooms were viewed as a plague. Every time one sprouted, the townspeople would vigorously clean the location with the heaviest grade of industrial cleaner, the kind you have to wear masks and gloves to use safely.

They weren't a poisonous variety, but neither did they taste very appealing. Something like a cross between grass and sandpaper. They served no good purpose, and the way they kept multiplying to the point where it seemed you were walking, sitting, and sleeping on mushrooms was creepy.

But when the town survived the alien invasion, people stopped complaining about the mushrooms.