In the story, Lord Canterville warns Mr. Otis about the ghost by telling him of its existence. In addition, Lord Canterville tells Mr. Otis about his family's experience of living at Canterville Chase and, specifically, of the ghost's activities. Lord Canterville recalls, for instance, how the ghost terrified his aunt, the Dowager Duchess of Bolton, by placing two "skeleton hands" on her shoulders as she dressed for dinner.
Lord Canterville also claims that the ghost has been seen by several other people, including the Rev. Augustus Dampier.
Lord Canterville makes it very clear to Mr. Otis that the only reason he has sold Canterville Chase is because of the ghost. The young servants refused to stay there at night, for instance, and his wife, Lady Canterville, could not sleep because of the noises made by the ghost.
Despite his warnings, Mr. Otis is not put off: he buys Canterville Chase and immediately moves in with his family.