Police Drones

Brought into Paragon City by the PPD after the Rikti War, the Paragon City Police Drones are small hoodlight-looking robots that patrol Paragon City and keep citizens (and heroes in need) safe. There are usually two stationed at every entrance to a different zone, and the Yellow and Green Line stations, as well as important areas (i.e. around Atlas Plaza) to the city.
The Police Drones are also stationed heavily around the hero bases in Player Vs. Player zones such as Warburg, along with plentiful Longbow, so Villain Players (especially Stalkers) are unable to assassinate heroes loading into the zone.
The drones are absolutely invincible, have absolute accuracy to all villains, and always defeat villains in one hit, no exceptions; even in PvP.