Knock knock. Who's there? Alpaca.

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

Knock knock. Who's there? Sew

Sew who? Sew long, I've been trying to weave a good joke.

Knock knock. Who's there? Otto.

Otto who? Otto know by now that Otto-matically, I'd bring an out-of-this-world pun like this right to your door!

Knock knock. Who's there? Elijah.

Elijah who? A light bulb just went off, I've got a brilliant idea for a joke!