Deceptive patterns are interface design strategies that manipulate users in their decision-making against their best interests. They are common in websites and apps, cost users time, money, or personal data, and often lead to anger and frustration. This makes sensitizing people about them increasingly important. This is the goal of Whack-a-Pattern. Inspired by the classic arcade game Whack-a-Mole, Whack-a-Pattern has players shatter as many deceptive patterns as they can using a (soft) physical hammer while sparing fair designs, in a fast-paced, high-energy game. Whack-a-Pattern approaches the rather dystopian topic of deceptive patterns from a new and irreverent, fun perspective. It is accompanied by a version of the game that can be played online to educate and spark interest in deceptive patterns among the research community and beyond.