Breadcrumb: He's mad!

Early on in our narrative, David runs away into the land of Gath. It turns out, though, that King Achish has heard of David's battle-prowess. David gets worried at this point, perhaps because he thinks Achish will see him as a potential rival. So when the servants drag him before the king, he pretends to be a madman, writing on doorposts and drooling into his beard. The king falls for it hook, line, and sinker, and asks his servants why they've brought yet another madman before him: "Am I so short of madmen that you have to bring this fellow here to carry on like this in front of me?" David gets away, and Achish loses the chance to kill the future king of Israel. Which just goes to show you, acting skills can save your life. (1 Sam. 21:10-15, NIV)