1 Samuel 21:13

And David laid up the words in his heart, and was greatly afraid of Anchus king of Geth.

And he changed his appearance before him, and feigned himself a false character in that day; and drummed upon the doors of the city, and used extravagant gestures with his hands, and fell against the doors of the gate, and his spittle ran down upon his beard.

And he changed his behaviour before them, and feigned himself mad in their hands, and scrabbled on the doors of the gate, and let his spittle fall down upon his beard.