What several places in the novel do kids gang up on other kids?

In the chapter, Alien, Auggie is attacked by Jack.

I knew that was a lie, but I helped Jack get up, and we started walking over to Amos. Then out of the blue, the Eddie guy grabbed my hood as I passed by him, yanking it really hard so I was pulled backward and fell flat on my back. It was a hard fall, and I hurt my elbow pretty bad on a rock. I couldn’t really see what happened afterward, except that Amos rammed into the Eddie guy like a monster truck and they both fell down to the ground next to me.

Everything got really crazy after that. Someone pulled me up by my sleeve and yelled, “Run!” and someone else screamed, “Get ’em!” at the same time, and for a few seconds I actually had two people pulling the sleeves of my sweatshirt in opposite directions. I heard them both cursing, until my sweatshirt ripped and the first guy yanked me by my arm and started pulling me behind him as we ran, which I did as fast as I could. I could hear footsteps just behind us, chasing us, and voices shouting and girls screaming, but it was so dark I didn’t know whose voices they were, only that everything felt like we were underwater. We were running like crazy, and it was pitch black, and whenever I started to slow down, the guy pulling me by my arm would yell, “Don’t stop!”