system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do black houseflies rub their legs together like as if they are plotting something?
gpt
They're cleaning them selves. When they rub their legs together, it gets all the grime, oil, and dirt, and forms it into a little shit ball that they get rid of (i think they eat it). Then they just keep doing it over and over again, until they cant form any more shit balls.