Oh, and he told me one more thing.

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

You can hear this line at 00:58:41.619 in the Blu-ray version of the movie.

Quote context

[...]

- So he says, 'How would you like to be rich?' So I said, 'Sure.' So he lays this book on me.

- He says this book will tell me the outcome of every sporting event till the end of the century.

- All I have to do is bet on the winner, and I'll never lose.

- So I said, 'What's the catch?' He says, 'No catch. Just keep it a secret.'

- After that, he disappeared. I never saw him again.

- Oh, and he told me one more thing.

- He said, 'Someday a crazy, wild-eyed scientist, or a kid may show up asking about that book. And if that ever happens...'

- Funny. I never thought it would be you.

- Yeah, well, Biff, you're forgetting one thing.

- What the hell is that?

[...]