How are you supposed to react when someone asks a question like that?
“If you ever visit the dark side of the moon, you’ll come to know what they are”, one is tempted to answer. Maybe something better or more sarcastic and cryptic? Then on second thoughts you think about the numerous things you have no idea about.
“I am sorry, Norman Frankestein what?” (Sorry Mr Finkelstein)
Ah those embarrassing moments. So you decide to forgive them. And explain them how the “what” they are asking about is one of the most awesome things that happened to mankind. And then be happy that you contributed in the enlightenment of someone.