Creeper World is a series of web browser and standalone video games with both real-time strategy and tower defense elements developed by Knuckle Cracker. Players must survive the onslaught of the titular blue mass, known as Creeper, which rises up the playing field and attempts to destroy their base of operations, Odin City. This is achieved by gathering energy and using it to power weapons which stave off the Creeper long enough for the player to link Odin City with each level's energy totems in order to escape to the next level.