Look, it works. The kryptonite can stop Superman.
3 seconds sound clip from Superman (1948) - Superman In Danger (Chapter 6).
You can hear this line at 00:03:22.753 in the Blu-ray version of the episode.
Quote context
[...]
- Again, Superman makes use of his x-ray vision.
- Superman, how can I ever thank you?
- Don't try now. You'll be seeing me again.
- Stop kidding, I'm not in the mood for fun.
- This kryptonite is supposed to handle him.
- Look, it works. The kryptonite can stop Superman.
- A good job well-done, gentlemen. Thank you.
- With Superman under control... the job should be easier.
[...]