Freak has an allergic reaction to the chop suey.
Max ("the Mighty" part of "Freak the Mighty") is having a tough day. His teacher tried to get him to answer questions alone, and the principal told him that his father wanted him to talk to the parole board. When Max and Freak have lunch, Max comments on how much Freak enjoys chop suey.
Freak has this thing about American chop suey. He loves the stuff. The gooier the better. You'd never believe a person so small could eat so much, and when he holds up his plate, he always says, "Please, sir, more gruel" … (Ch. 13)
This is a reference to Oliver Twist, but Max does not read as much as Freak, so he does not understand it. He just tells Freak that it’s chop suey, not gruel, and goes to get him some more. Yet when he returns, he finds something very frightening. His friend is turning colors! He is having an allergic reaction.
Back in the cafeteria, Freak is turning purple. The nurse grabs him and she's got this plastic thing she shoves into his' mouth and his eyes are closed up tight and one of his legs is kicking. (Ch. 13)
Fortunately, this helps, and Freak is okay, but still has to go to the hospital. Still, it has been a tough day for Max, who comments again that it is Friday the Thirteenth, and that is why everything is going wrong. The principal Mrs. Addison tells that he has had quite the day, and he responds:
"It's not me who had quite a day," I say. "Kevin-is the one. All he did was try and eat his lunch." (Ch. 13)
She is aware that he is worried about Freak, his father, and school. When he went into her office earlier, he was concerned that she was going to put him into a class for learning disabled students, so she is aware that he thinks about this.
Max’s friendship with Kevin is one of reciprocation. Kevin relies on Max for his strength, and Max relies on Kevin for his brains. However, they both do genuinely care about each other. As this chapter demonstrates, though, they have begun to rely on each other to the point where they are actually almost inseparable, and twice Max has to confront the possibility of not having Kevin there.