A gaming machine is provided that provides games in which a plurality of symbols are selected from a group of symbols and displayed on a display and, if a winning combination occurs, the gaming machine awards an award. The gaming machine comprises a user interface in communication with a game controller. The game controller is configured to provide a first game in which an event counter is maintained by the game controller and modified by the game controller each time a counter event occurs, and to provide a second game in which the game controller modifies the group of symbols to include a number of specific symbols. The number of specific symbols is dependent on the value of the event counter.