Knock knock. Who's there? A pause.

A pause who? No, just a pause. The joke's over.

Knock knock. Who's there? Hearse.

Hearse who? Hearse a real groaner for ya: I used to be a baker, but I couldn't make enough dough to roll with the big timers!

Knock knock. Who's there? Alpaca.

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

Knock knock. Who's there? Pane

Pane who? I'm having a window of opportunity to let you in.