The Bat-Signal is a distress signal device appearing in American comic books published by DC Comics, as a means to summon the superhero, Batman. It is a specially modified searchlight with a stylized emblem of a bat affixed to the light, allowing it to project a large bat symbol onto the skies over Gotham City. The signal is used by the Gotham City Police Department as a method of contacting and summoning Batman in the event his help is needed, but also as a weapon of psychological intimidation to the numerous criminals of Gotham City.