airplay icon won't go away

Today I noticed that the AirPlay icon has appeared on my menu bar. I am pretty sure it wasn't there before, because I had tried to clear my excessively cluttered menu bar and would have noticed it. I do not own an Apple TV or anything but in the menu I can see a bunch of other people's screens in my apartment complex. Despite the fact that AirPlay is off, and I have unchecked "show mirroring options" in System Preferences:Displays, and then quit System Preferences. If I force quit AirPlayXPCHelper in Activity Monitor, the icon disappears and immediately reappears (and the process is back in Activity Monitor).

Doing a search, it seems that most people have the problem of not being to see the AirPlay icon. Although I did see one person mention a security problem involving AirPlayXPCHelper. I hope that's not what's happening with me? How do I get it to go away?