The Question and Answer section for The Adventures of Tom Sawyer is a great resource to ask questions, find answers, and discuss the novel.
When Injun Joe openly lies and frames Muff Potter for the murder, both Tom and Huck half expect "God's lightening upon [Injun Joe's] head" as punishment." When they see Joe again they think that he probably sold his soul to the devil.
In Chapter Six, Tom wants to skip school, citing his sore tooth as a reason to stay home. He gets his "just deserts" when Aunt Polly pulls out his tooth and sends him off to school.