Witch of Endor:
Just prior to a massive battle with the Philistines, King Saul decides to consult a medium to contact Samuel (who was dead at the time, and had been for a while).
This was in spite of the ruling he himself had made banning all mediums and psychics from Israel.
He went to see the woman (often called the Witch of Endor) in disguise.
She summoned up Samuel who told him that he would be defeated, as the Lord had given his kingdom over to his rival, David [1 Samuel 28].
Sure enough, Israel was defeated by the Philistines, who find Saul's dead body, cut off his head, put his armour in their pagan temple and fasten his (headless) corpse to the city wall [1 Samuel 31:8-10].