Conan the Librarian is a prank app where Conan tells you to shut up when the incoming sound on your built in microphone reaches certain levels. This is a port of a very, very old System 7 extension for the Macintosh.
Simply double click the icon to launch. It runs as a faceless background application, so it will look as if nothing has happened. When running, Conan the Librarian listens in on the built in microphone. When the sound level gets to a certain point, it will tell you to shut up. If you need to kill the application because your life is being threatened, open up a Terminal window and type in the following command: killall QUIT "Conan The Librarian"