The Vibraslap, also known as a jawbone or chatterbox is a percussion instrument that is very simple to play. Strike the ball with the palm of your hand and the vibration will travel through the metal wire, into the resonator box, which in turn rattles the metal teeth inside of it creating a chattering sound.
Although most often used as a sound effect in films or for comedic effect, it has been used in well known rock songs such as: Ozzy Osbourne's 'Crazy Train' and 'Sweet Emotion' by Aerosmith.