Sword of Damocles

This is a peril or danger hanging over one. The reference is to the legend that Damocles, a courtier of ancient Syracuse, used to try to curry favor with his king by talking about the wondrous ease of the kingly life. In order to teach him the lesson that perils and responsibilities also accompany the privileges of kingship, King Dionysius invited Damocles to a banquet, where he was seated under a sword hanging by a single thread, Damocles was so distraught that he could not enjoy any of the sumptuous repast set before him.