That night I learned that more than 150 baseballs had gone over that fence and not one of them was ever seen again...
10 seconds sound clip from the The Sandlot (1993) movie soundboard.
You can hear this line at 00:32:27 in the Blu-ray version of the movie.
Quote context
[...]
- Nuh-uh. No. None of that's true. You guys are just making this up to scare me.
- Oh, yeah? Stick your head out that window and look down.
- I knew it was true. Because when I looked down in there, I didn't see a single solitary one.
- Whatever goes over that fence stays there.
- It becomes the property of The Beast forever.
[...]