Lie detector

A man buys a lie detector robot which slaps people who lie.
He decides 2 test it at dinner one night.


DAD: Son, where were you today during school hours?
SON: At School.
Robot slaps son!
SON: Ok, I lied, I went to the movies.
DAD: Which one?
SON: Toy Story.
Robot slaps son again!
SON: Ok, it was porn.
DAD: ...What?! When I was your age, I didn't even know what porn was
Robot slaps Dad!
MOM: forgive him dear, after all he is your son.
Robot slaps mom...
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