He knocked again and heard again the high pitched "Come In." As he entered the kitchen a large, mean, snarling Doberman met him.
He plastered himself against the wall, called out for help, and again heard the "Come In." He slid down the wall to the living room and found a parrot in a cage.
He said, "For Pete's sake, is that all you can say -- Come In?" The parrot laughed and said "Sic Him!"