Knock knock. Who's there? Existential Crisis.

Existential Crisis who? I'm not sure, I've been questioning the meaning of my own existence and the nature of identity, so the concept of a 'who' is somewhat fluid to me.

Knock knock. Who's there? Taco.

Taco who? Taco 'bout a good time!

Knock knock. Who's there? Egg

Egg who? Egg-cuse me, I'm cracking under the pressure to make a good pun.

Knock knock. Who's there? Noah.

Noah who? Noah body's home, I'm ark-ing around for someone to let me in.