Knock knock. Who's there? Fig

Fig who? Fig-ure it out yourself!

Knock knock. Who's there? Wheat

Wheat who? Wheat you waiting for, let me in

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? Silence.