What is Maudie suggesting about Mr Radley and his treatment of Boo?

Miss Maude is trying to scare Scout by telling her about Boo Radley. Most of the town is afraid of him because he is a recluse and a lot of people haven't seen him in years. They imagine him to look terrible and to be very mean, when in fact he is a good person and he ends up helping Scout and Jem later in the story.