Are You Lying?

A dad buys a lie detector robot which slaps people when they lie. He decides to test it at dinner. " Son, where were you today? " The son says " At school, dad." Robot slaps the son!!! " Ok, i watched a dvd at my friend's house!" " What DVD? "

" Toy Story." Robot slaps the son again! " Ok, it was a porno!" cries the son. "What!? When i was your age i didn't know what porn was! " says the dad. Robot slaps the dad! Mom laughs " Hahahaha! He's certainly your son." Robot slaps the mom.