John McNab is a "giant." He is five feet eight inches tall, weighs one hundred and seventy pounds, and is only 12 years old. He pitches for one of the Little League teams in Two Mills. He is "like a shark," because he strikes out all of the players on the opposing team with his fastball. When Maniac arrives in Two Mills, not only does he hit McNab's fast ball, but he hits home runs and humiliates McNab. To retaliate, McNab and his group of friends (they call themselves the Cobras) chase Maniac into the East End. McNab and the Cobras stop at Hector Street, the dividing line between West End where the whites live, and East End where the blacks live. They laugh, believing they have inflicted the worst possible punishment on Maniac.
Later in the novel, when Maniac returns Russell and Piper (John's younger brothers) to the McNab household, John is grateful. Maniac ends up staying at the McNabs' even though it is a chaotic and filthy environment. Maniac meets John's father and feels uneasy because John's father appears to be a racist. He also observes the McNabs and the Cobras building a fortress (a "pillbox") out of cement blocks — in the living room of the house. The fortress is a defense against "today's Indians," the blacks, when they revolt. Because of John's ignorance of black people and his father's racist influence, he is prejudiced toward black people.
When Maniac brings Mars Bar to the McNab house for Piper's birthday party, John attempts to intimidate Mars Bar and cause Mars Bar to initiate a fight. Maniac intercedes and Mars Bar criticizes the disgusting condition of the McNab house. Because Maniac defends Mars Bar, and because Maniac is viewed as a hero in Two Mills, it is logical to assume that after the interaction between John and Mars Bar, John views black people differently. However, Spinelli does not reveal any changes that take place regarding John's attitude toward black people; this issue is left to the reader to decide.
