Dad buys a lie detector robot which slaps people when they lie.

He decides to test it out on his son.

“Son, where were you today?”

The son says, “Watched a DVD at my friend’s house!”

“What DVD?”

“Toy Story!”

The robot slaps the son!

“Ok, it was a porno” cries the son

“What! When I was your age I didn’t know what porn was” says the dad

The robot slaps the dad!

The mom laughs, “He’s certainly your son!”

The robot slaps the mom!