What did macbeth see before me?

Macbeth has made his decision to kill the King and take the crown as his own. Inspired in part by his own ambition, the decision to murder Duncan is aided by the prophecies of the Witches as well as the insistent urging of his wife. Still, Macbeth is wracked with guilt over what he is about to do, and his mind races with thoughts of such evil action. He begins to hallucinate and sees a bloody dagger in the air, which will be his instrument of murder. He goes on to comment on the wickedness of the world, thoughts which are interrupted by the ringing of the bell, a signal from Lady Macbeth that Duncan's guards are drugged and sleeping. He goes off to complete the dire deed. Shakespeare's Macbeth is notable for hallucinations, terrifying dreams, witches, prophecies and all of the combining forces of nature which lead to chaos and murder in the gloomy countryside of Scotland.