Don't tell me there are two of them.
2 seconds sound clip from Scooby-Doo, Where Are You! - Bedlam in the Big Top (S1E10).
You can hear this line at 00:18:16.086 in the Blu-ray version of the episode.
Quote context
[...]
- Here, Shaggy! Huh? Where did he go?
- Over here. Here I am. What are you waiting for?
- So, they think they have escaped me. Ha ha ha!
- Man, he's after us. Back to the cage and the hero sandwich! He's coming! Drop the door!
- Good work, gang. Now we'll unmask the ghost.
- You fools will never capture the ghost clown! Ha ha ha ha ha ha!
- Don't tell me there are two of them.
- Look! The one in the cage is gone.
- I can't believe it. I would have bet money we had him.
- Money? Hey, that's it. A gold coin!
- I have an idea about this ghost, Scooby, and we're going out again.
- Ha ha ha ha! Watch the pretty coin of gold, and you both shall do as you are told.
[...]