How did Maniac embarrass McNab?

I believe that this question is asking about an event that is found in chapter 7. Maniac shows up at the town's Little League baseball field, and McNab is preening like a peacock after striking out a record 35 kids in a row. He just lines them up and keeps pitching. Maniac steps to the plate and hits McNab's first pitch. It is a line drive right back at McNab's head.

McNab fired. The kid swung. The batters in line automatically turned their eyes to the backstop, where the ball should be—but it wasn't there. It was in the air, riding on a beeline right our to McNab's head, the same line it came in on, only faster.

McNab throws pitch after pitch, and Maniac just keeps hitting them farther and farther. McNab eventually decides to try and hit Maniac with a pitch, but Maniac just dodges the attempts. Finally, McNab decides to throw a pitch at Maniac nobody anticipates. He uses a frog instead of a ball.

It wasn't a ball at all, it was a frog, and McNab was on the mound cackling away, and the kid at the plate was bug-eyed. He'd never—nobody'd ever—tried to hit a fastfrog before.

Maniac bunts the frog and takes off to first base. Maniac is on his way to second base before McNab even realizes what is happening, and Maniac gets himself an inside-the-park home run from bunting a frog ball and breaking McNab's strikeout streak.