How does the author begin building a tone of suspense and danger in this chapter? Provide evidence from the book to support your answer.

Percy is stunned, and goes back to his class—his classmates, however, claim that they have never had a Mrs. Dodds as a teacher and they have no idea what he is talking about.

Back at school, the students continue to deny Mrs. Dodds' existence. Percy knows something has happened, and it makes him irritable, so his grades begin to slip and he gets in trouble often. The headmaster sends his mother a letter saying he will not be invited back to Yancy Academy.