Goosebumps 34 - Revenge of the Lawn Gnomes

The book opens with a ping pong game. At one point protagonist Joe Burton serves the ping pong ball by kicking it instead of using the paddle, much to his older sister Mindy's chagrin. He then follows that by telling her there's a spider on her back. Joe reveals that he doesn't look like anyone else in the family. They're all tall and skinny and he's short and stout.