Knock knock. Who's there? Tell me.

Tell me who? No, *you're* supposed to tell *me* who's there. I'm the one who knocked, and now I'm waiting.

Knock knock. Who's there? Cows go.

Cows go who? No, cows go 'moo'.

Knock knock. Who's there? Alpaca.

Alpaca who? Alpaca the suitcase if you open the door!

Knock knock. Who's there? Peas.

Peas who? Peas-fully waiting for you to open the door!