The introduction of the ghost adds mystery to the story, which naturally attracts the audience as it makes people want to find out more. Moreover, even though the ghost does not speak, his clothes reveal that he is King Hamlet. This suggests to the audience that the King has some kind of unfinished business, or that there is something important that he wants to communicate. This forces the audience to wonder what the business might be and what this means to the future of the kingdom.
