Now I may have seriously altered history.
3 seconds sound clip from the Back to the Future Part III movie soundboard.
You can hear this line at 00:46:34.915 in the DVD version of the movie.
Quote context
[...]
- 100 years ago! That's this year!
- Then she was supposed to go over in that wagon.
- Now I may have seriously altered history.
- Look, Doc, what's the worst that can happen, huh?
- So they don't name the ravine after her.
- Let's just get the DeLorean ready, and get the hell out of here.
- I wish I'd never invented that infernal time machine. It's caused nothing but disaster.
- Doc, Doc, this is Marty. Do you read me? Over.
[...]