In the play "Macbeth," Shakespeare uses elements of the supernatural is a key part of the structure of the plot. Incorporating the mysteries of the mythical provides an incentive for action, an insight into the characters, and plays an important role in how many of they key scenes unfold. Throughout the play, the supernatural is portrayed to the audience in a variety of forms. Some of these forms include ghosts, floating daggers, witches, and prophetic apparitions. Supernatural aspects are a recurring theme in many of the plays written by Shakespeare, Macbeth being one of the most famous. It is thought that the supernatural appeals to the audience's curiosity of the mysterious and thus strengthens their interest in the play.
Of all the supernatural phenomenon happenings in Macbeth, the witches and their prophecies seem to be the most prominent. The trio represent Macbeth's evil ambitions, and from their appearance in the first scene of act one to their last prophetic encounter with Macbeth, they add an eerie aspect and haunting atmosphere to the play. Referred to as "dark instruments" by Macbeth, he seeks them out in their cave and demands to know if the prophecies given to him are true. He wants to know the answers to his questions regardless of the outcome. The witches are the catalyst which unleash Macbeth's evil aspirations, and provide him with incentive to act in ways that are violent and destructive to nature. Although the witches add ghoulish facets to the play, they also intrigue the audience to keep reading or watching to find out if their prophecies come true. .
The appearance of Banquo's ghost provides insight into Macbeth's character. The ghost serves to show the path that Macbeth could have chosen, as well as a reminder of Macbeth's previous deeds. The ghost admonishes Macbeth of the horrors he has committed to gain the crown, and the innocent blood spilled by his actions.