The consequences of that could be disastrous!
2 seconds sound clip from the Back to the Future Part II movie soundboard.
You can hear this line at 00:25:54.186 in the Blu-ray version of the movie.
Quote context
[...]
- Home? To Hilldale? It'll be dark by the time we get out there.
- That's it. They're taking her home. To your future home!
- We'll arrive shortly thereafter, get her out of there and go back to 1985.
- You mean I'm gonna see where I live? I'm gonna see myself as an old man?
- No, no, no, Marty. That could result in...
- Oh, Great Scott! Jennifer could conceivably encounter her future self!
- The consequences of that could be disastrous!
- I foresee two possibilities.
[...]