- I didn't mean to startle you.
- I don't know what made me do that.

3 seconds sound clip from the Creature from the Black Lagoon (1954) movie soundboard.

You can hear this line at 00:18:43.506 in the Blu-ray version of the movie.

Quote context

[...]

- I've always found Kay was able to take care of herself.

- But we know nothing about this lagoon.

- I can tell you something about this place. My boys call it the Black Lagoon, a paradise. Only, they say nobody has ever come back to prove it.

- We'll do it.

- Oh! Oh, David.

- I didn't mean to startle you.

- I don't know what made me do that.

- That howling out there doesn't help any.

- Those are guariba monkeys.

- You sorry now that we came?

- You don't understand the species very well, Doctor.

- Well, give me time. I thought I was doing well, considering that we've only been together for six months.

[...]