The Magic Mean Machine

How can Alison Harrity beat bully Spencer Cunningham? Alison would have a good chance to win the fifth grade chess tournament—except that Spencer is cheating his way to the championship. And Alison isn’t pushy enough to stand up to him. Then Marvin Smith, a science wiz, invents the DISAST to help Alison get really tough. But is it worth it to win the tournament, if she loses all her friends?