Knock knock. Who's there? Nana.

Nana who? Nana your business!

Knock knock. Who's there? The door.

The door who? The door you just knocked on. It's not a person, it doesn't have a name.

Knock knock. Who's there? I forgot

who? Oh wait, I remember now, but it's not like it matters because I'm just going to forget again anyway.

Knock knock. Who's there? Ismael.

Ismael who? Ismael a rat in here, or is this just the *cheesy* aroma of my latest pun-demic?