What are some discriminating things Erik does?

From the text:

I watched them in disbelief. How could they be happy? Who were these two people? Then I realized it: They were the two people who will benefit from Mike Costello's death. And they were celebrating it. Erik grabbed at Arthur's shoes and screamed in a high-pitched voice, "The shoes! Gimme the shoes!"

"Hey. Nobody who's worth thinking about is laughing at Mike. Or at you. Who are we talking about here? Erik? Erik's laughing at everybody. It's all a big joke to him. Arthur Bauer? He's a big zero. But now he's getting his chance, right? He's gonna hold the ball for Erik. But he's no Mike Costello. Nowhere near. He doesn't have the talent. He doesn't have the character. So what's he going to do? He's going to mock him.

Erik pointed to us and spoke with mock admiration. "Look at this. I think it's great that these farm-labor kids get to spend a day away from the fields."

Immediately, faster than I thought he could, faster than Tino thought he could, Erik lashed out, smashing the back of his hand across Tino's face, smashing him so hard that Tino spun halfway around in the air and landed on the grass.