Gaming devices, gaming systems, methods of conducting a wagering game, and computer programs for initiating a wagering game are presented herein. A gaming system is presented that includes a wager input device, a display, and a controller. The wager input device receives wagers from players to play the wagering game. The display displays outcomes of the wagering game. Prior to displaying the outcome of the wagering game, the controller determines whether to add at least one symbol clump to at least one of a plurality of reels. A symbol clump comprises one or more identical symbols occupying two or more symbol positions located immediately adjacent one another on one reel. In response to a determination to add at least one symbol clump, the controller instructs the display to visually indicate the addition of the symbol clump to the reel, and to display the outcome of the wagering game.