In the old days, long ago, grandparents, or an older person would tell scary stories to entertain children...perhaps at night when they were about to go to sleep. These stories might be made up or created on-the-spot, and usually included a frightening person, like "Old Soap-Sally", or "the boogy man", or someone spooky. In this modern day we just read books to children, but some will remember the old spooky stories that were told. Bony would probably be similar to a frightening skeleton, or thin old witch in the story.