Marty, come in.
2 seconds sound clip from the Back to the Future Part II movie soundboard.
You can hear this line at 01:24:40.334 in the Blu-ray version of the movie.
Quote context
[...]
- Look! How did he get up on stage?
- I don't know, but when he gets down, we're gonna nail him.
- How the hell did he change his clothes so fast?
- All right, it's an oldie where I come from.
- Listen, Biff's guys chased me into the gym, and they're going to jump... me!
- No, Doc, not me. The other me. The one that's up on stage playing Johnny B. Goode.
- Wait, wait, wait. A paradox? You mean one of those things that can destroy the universe?
[...]