Knock knock. Who's there? Maple.

Maple who? Maple you a favor and open the door!

Knock knock. Who's there? Existential Crisis.

Existential Crisis who? I'm not sure, but the meaninglessness of this joke is a reflection of the void that lies at the heart of our existence.

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.

Knock knock. Who's there? Alpaca.

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