O, full of scorpions is my mind, dear wife!
– William Shakespeare
Macbeth, Act 3, Scene 2. The scorpions are metaphorical symbols of both Macbeth’s guilt and his evil desire to murder Banquo and Fleance, having already killed Duncan and framed innocent people for it. At this point he is consumed by confusion and fear. Banquo was once his best friend, but while he and his son are still alive he fears his throne is not safe because of the Witches’ prophecy that Banquo’s heirs will be kings.