- Wait, wait, wait. A paradox? You mean one of those things that can destroy the universe?
- Precisely!

Marty Mcfly (Michael J. Fox)

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

You can hear this line at 01:24:56.850 in the Blu-ray version of the movie.

Quote context

[...]

- Marty, come in.

- Listen, Biff's guys chased me into the gym, and they're going to jump... me!

- Then get out of there!

- No, Doc, not me. The other me. The one that's up on stage playing Johnny B. Goode.

- Great Scott! Your other self will miss the lightning bolt at the clock tower, you won't get back to the future, and we'll have a major paradox!

- Wait, wait, wait. A paradox? You mean one of those things that can destroy the universe?

- Precisely!

- Marty, you have to stop those guys at all costs, but without being seen by your other self or your parents.

- 10-4.

- What the hell? (3)

- Where is he?

- Who?

- Calvin Klein.

- Who?

- The guy with the hat, where is he?

- Oh. He went that way.

[...]