A man buys a lie detector robot that slaps people who lie. So he decides to try it out at dinner.

Dad: Son, where were you today during school?

Son: At school *Robot slaps son*

Son: Ok, I went to the movies.

Dad: Which one?

Son: Toy Story *Robot slaps son again*

Son: Ok, it was A Day with a P*rn Star.

Dad: What?! When I was your age, I didn’t even know what p*rn was. *Robot slaps dad*

Mom: Haha!! Like father like son. After all he is your son, *Robot slaps mom*