"She might even be your lovely school-teacher who is reading these words to you at this very moment. Look carefully at that teacher. Perhaps she is smiling at the absurdity of such a suggestion. Don't let that put you off. It could be part of cleverness.

I am not, of course, telling you for one second that your teacher actually is a witch. All I am saying is that she might be one. It is most unlikely. But--here comes the big "but"--not impossible."
— Roald Dahl (The Witches)