You damn fool! Never, never leave this book laying around. Don't you have a safe? No, you don't have a safe. Get a safe. Keep it locked up. And until then, keep it on you like this.

Biff Tannen (Thomas F. Wilson)

14 seconds sound clip from the Back to the Future Part II movie soundboard.

You can hear this line at 01:09:59.663 in the Blu-ray version of the movie.

Quote context

[...]

- What are you, deaf, old man? He just said it was over. You lost.

- Oh, yeah?

- Here comes Decker with the kick. It's up. It looks good, folks! It looks very good. Field goal! UCLA wins 19-17. Listen to that Coliseum crowd go wild. Jim Decker...

- All right, pops. What's the gag? How did you know what the score was gonna be?

- I told you. It's in this book.

- All you gotta do is bet on the winner, and you'll never lose.

- All right. I'll take a look at it.

- You damn fool! Never, never leave this book laying around. Don't you have a safe? No, you don't have a safe. Get a safe. Keep it locked up. And until then, keep it on you like this.

- Hey, what are you doing?

- And don't tell anybody about it, either.

- Oh, and there's one more thing.

- One day, a kid or a crazy, wild-eyed old man who claims to be a scientist is going to come around asking about this...

[...]