Mars Bar is tough, used to getting his own way, and easily offended. He likes to be feared.
Mars Bar is one of the kids that Maniac meets in Two Mills. He is a tough guy, and also happens to be black. Mars Bar finds Maniac puzzling. He expects him to cower and back down, like everyone else does. Maniac doesn’t, and Mars Bar is not sure how to react.
The first baffling encounter occurs when Mars Bar offers Maniac a bite of his candy bar, and the boy actually bites. All of the neighborhood kids are shocked. Such a thing is simply not done.
The kid had done the unthinkable, he had chomped on one of Mars's own bars. Not only that, but white kids just didn't put their mouths where black kids had had theirs ... And the kid hadn't even gone for the unused end; he had chomped right over Mars Bar's own bite marks. (Ch. 10)
Mars bar gets angry, because “when Mars Bar got confused, he got mad.” He tries to get Maniac to tell him he’s “bad,” to confirm that he intimidates him, but Maniac does not comply. They fight over Maniac’s book, but even that doesn’t get much of a rise out of the boy. Mars Bar has a reputation to uphold.
Mars Bar glared up at her. There wasn't an eleven- year-old in the East End who could stand up to Mars Bar's glare. In the West End, even high-schoolers were known to crumble under the glare. (Ch. 10)
Amanda stands up to Mars Bar. She and Maniac seem to be the only ones who do. Amanda is tough, though. Mars Bar tries to get his reputation back, but Maniac makes a fool out of him when he races him and runs backward. Maniac is not trying to insult Mars Bar. He is just a bit odd.