From the book:
First grade babies!
Second grade cats!
Third grade angels!
Fourth grade rats!
Suds wishes he were still in third grade so he could keep on being an angel. But his best friend, Joey, is proud to be a rat, which he calls the next step up to being a man. According to Joey, fourth grade rats aren't afraid of spiders, don't carry babyish lunch boxes, and they don't cry. What rats do is push little kids off the swings, say no to their mothers, and eat real meat (like baloney). Becoming a real rat doesn't sound too good to Suds.