"Knock, knock."
"Who's there?"
"Who."
"Who who?"
"Why are you who-ing like an owl?"
"Knock, knock."
"Who's there?"
"Who."
"Who who?"
"Why are you who-ing like an owl?"
Alright, listen up, you chucklehead. This is a knock-knock joke. Someone says "Knock knock," and you say, "Who's there?" Then they give you a name, and you say the name plus "who?" Then they tell you the joke. In this case, the name sounds like an owl hooting. You probably spend your weekends trying to figure out how to open a jar of pickles, don't you?