Something wicked this way comes
By the pricking of my thumbs,
Something wicked this way comes. [Knocking]
How now, you secret, black, and midnight hags!
What is't you do?
After conjuring up "double, double toil and trouble" [see
p. 32], the three witches admit a visitor to their cave—King
Macbeth of Scotland. "Something wicked this way comes," indeed, and
they're delighted. Macbeth—at least, the wicked Macbeth—is in part
their own creation. The first time around, they came looking
for him, to deliver the enticing prophecy that set off the
whole chain of events which has included Macbeth's regicide and
subsequent bloody events. Now, Macbeth comes looking for
them, and the witches summon apparitions to tell Macbeth
exactly what he wants to hear: that he's invulnerable. This news is
purposely ambiguous; it is calculated only to make Macbeth act more
wickedly before he is finally finished off.