What does the dagger represent?

In Act Two, Macbeth hallucinates a dagger floating in front of him and longs to clutch its handle. The dagger symbolizes the treacherous and doomed path that Macbeth will travel for the rest of the play, starting with the murder of Duncan and continuing with the murders of anyone who threatens Macbeth's crown. In this way, the dagger – which Macbeth sees as a sign of his own power – foreshadows Macbeth's own doom without his knowledge.