Knock knock. Who's there? Cereal

Cereal who? Cereal-ly good at making bad jokes, it's a grain of truth!

Knock knock. Who's there? Nimbus.

Nimbus who? Nimbus sure I'm at the right door, the forecast said I'd find you here!

Knock knock. Who's there? Otto B.

Otto B. who? Otto B. a crime if you didn't laugh at that groan-worthy pun!

Knock knock. Who's there? Knock

knock. Who's there? *sigh* Never mind.