My father bought a robot that will slap anybody who lies and wanted to test it at dinner:
Dad: Son, where were you during school?Son: School
The robot slaps the son
Son: Okay, I saw a movie with friends
Dad: What movie?
Son: Kung Fu Panda
The robot slaps the son
Son: Okay! It was porn
Dad: What?! At your age I did not know about porn!
The robot slaps the dad
Mother: Ha ha ha, after all he is your son
The robot slaps the mother