The prize system (also called the point system or checkpoint system) is a type of reward system in The Simpsons: Tapped Out. It was first seen in the Whacking Day 2013 Event, when the player had to collect snakes in order to win prizes. It was unique to other aspects of the game, as the balance of currency (e.g. snakes or GOO) accumulated and could not decrease. For example, prizes were staggered on milestones with a top prize awarded when the player collects a certain amount.