a typical M. family conversation

Me: B! Sit still! What, do you have pinworms or something?

Uncle M: Pinworms?! What are pinworms?

Me (rather embarrassed that the textbook answer is still engrained in my memory): A type of parasite that lives on the anus of mammals.

Uncle M: Oh God! Really?! How big are they?

B (full of 14 y. o. snottiness): The size of a pin, DUH.

Uncle M: A bowling pin!? A clothespin?

...and so on and so forth...