Knock knock. Who's there? Next.

Next who? Next time, just open the door, this isn't a surprise party.

Knock knock. Who's there? Silence.

Knock knock. Who's there? Flour.

Flour who? I knead you to let me in, it's a loaf-ing matter.

Knock knock. Who's there? Alpaca.

Alpaca who? Alpaca the suitcase, we're going on vacation!