The Story Of The Lie detector

A father buys a lie detector robot that slaps you when you lie.

He decides to test it out on his son at supper. "Where were you last night?"

"I was at the library."

The robot slaps the son.

"OK I was at a friend's house," the son admits.

Doing what?" asked the father "Watching a movie: Toy Story."

The robot slaps the son.

"OK it was porn!" cried the son. Father yells "What? When I was your age I didn't know what porn was!"

The robot slaps the father.

The mother laughs and says, "He certainly is your son!"

The robot slaps the mother.