Knock knock. Who's there? Canoe.

Canoe who? Canoe let me in, it's freezing out here!

Knock knock. Who's there? Dictionary.

Dictionary who? I'm not defining the terms of this conversation.

Knock knock. Who's there? Parenthesis.

Knock knock. Who's there? Alpaca.

Alpaca who? Alpaca the suitcase, you load the car!