Knock knock. Who's there? No one.

No one who? Exactly. There's literally nobody here. I just wanted to see if the door was locked.

Knock knock. Who's there? Flake

Flake who? Snow-body's home.

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? Leaf.

Leaf who? Leaf me alone, I'm busy!