Macbeth's guilt and fear manifest in the form of Banquo's ghost, which only he can see.
Lady Macbeth tries to cover for Macbeth's strange behavior, but her efforts are in vain.
Macbeth's confidence is shattered by the ghost's appearance, revealing his inner turmoil.
Lady Macbeth believes the ghost is a product of Macbeth's fear and doubt.
Macbeth's weakness and insecurity lead him to rely on supernatural forces and prophecies.