Knock knock. Who's there? Alpaca.

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

Knock knock. Who's there? No one.

No one who? Exactly. There's literally nobody here. I just wanted to see if the door was locked.

Knock knock. Who's there? Elijah.

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

Knock knock. Who's there? Wu

Wu who? Wu don't know, I'm having an identity crisis, but I'm paws-itive I'll fur-get about it.