An example of foreshadowing in "Oedipus the King" is when Tiresias, the blind prophet, warns Oedipus that he is the murderer he seeks. This foreshadows the revelation of Oedipus' true identity and the tragic events to come. The foreshadowing is ironic because Oedipus, in his ignorance, dismisses Tiresias' words, but ultimately, they prove to be true, contributing to the tragic irony of the play.