Boy, you're not kidding. A couple of tons of earth that almost hit you.
3 seconds sound clip from the It Came from Outer Space movie soundboard.
You can hear this line at 00:12:27.464 in the Blu-ray version of the movie.
Quote context
[...]
- Come on, let's get out of here. Maybe you'll listen to me next time.
- John! John, are you all right? Johnny? Johnny.
- Well, then, what's the matter?
- There's something down there.
- Boy, you're not kidding. A couple of tons of earth that almost hit you.
- What do you mean? What was it you saw down there?
- I'm not sure. Some kind of a ship, I think.
- A what?
- A ship.
- I don't know. It's like nothing we've ever seen before.
[...]