How did Zeus come to Danae, the imprisoned daughter of Acrisius?

King Acrisius of Argos has been told by an oracle that he will never have a son but that his daughter will. But before Acrisius can start celebrating, the oracle goes on to tell him that this future grandson will kill him. Understandably spooked by the oracle's ominous prophecy, Acrisius resolves to make sure that his potential assassin will never be born. He won't kill his daughter, Danae, as that would incur the wrath of the gods. Instead, he puts her in an underground bronze chamber with only a single window for ventilation. This way, Danae will literally never see the light of day and will be unable to give birth to any future usurpers.
Unfortunately for Acrisius, the mighty Zeus has other ideas. The father of the gods desires Danae and wants to sire a child by her. So he comes down to her in the form of golden rain, which falls through the roof of the bronze chamber and into the princess's womb. Not long after, Danae gives birth to a son, Perseus, who will grow up to become a great hero and warrior.