At my parents house in one of the bathrooms, once a year those things when they have wings come from nowhere in the sink. Im talking hundreds, probably a thousand of them at once. All within the span of about 10 minutes. One minute youre washing your face or your hands. Ten minutes later, BAM, theres a shitload of these little guys in the sink. Every single year. I have no fucking idea how they come out of the drain. We just vacuum them up. And then they will show up in another year.