1 Samuel 21:14

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 Anchus said to his servants, Behold! you⌃ see the man [is] mad: why have you⌃ brought him in to me?

Then said Achish unto his servants, Lo, ye see the man is mad: wherefore then have ye brought him to me?