If anyone knew that, they could pierce the secret of our true identities.
6 seconds sound clip from the Batman (1966) movie soundboard.
You can hear this line at 01:05:46 in the Blu-ray version of the movie.
Quote context
[...]
- You'd be willing to submit yourself to a test?
- Why, of course. It might be an amusing experience, don't you know?
- Stand by to catch him, Robin. I'll give him the bat gas.
- Oh-ho, what's that? Bat gas?
- A harmless anesthetic necessary to prevent you from seeing the entrance to the Batcave.
- If anyone knew that, they could pierce the secret of our true identities.
- Oh, I say. What deucedly strange customs you colonials have. What? Well, I'm ready.
- To the Batmobile. This could be the break we've been looking for.
- He's the Penguin, all right. I wonder why he let us bring him here. We'll soon find out.
- I'll set up the anti-crime eye checker.
[...]