Whilst there are a number of location sensing games emerging for mobile phones there are few examples of social proximity based games that are effectively position independent and whose game play is invoked by serendipitous encounters. In this research we have extended the existing mobile phone phenomenon of Bluejacking, which allows spontaneous social encounters, into the design of a novel mobile game that creates instigates an exciting ludic scenario. The game is called ‘mobslinger’ which is based on the premise of a wild west, quick draw, ‘shoot-em-up’ In this game the phone scans continuously searches for other game players and when found instigates a ‘shootout’ were players ‘draw’ their phone and ‘shoot’ their opponent . This paper presents the design, and subsequent implementation, of the game which takes account of the limitations of the platform whilst maintaining the social nature of phone use to successfully create the serendipitous social encounters.