It's a spy... A spee... A spide... De... De... De... An arachnid!
12 seconds sound clip from the An American Tail: Fievel Goes West movie soundboard.
You can hear this line at 00:08:26 in the Blu-ray version of the movie.
Quote context
[...]
- Pay attention. Keep it clean and tidy. Plenty of violence, but no eating. Right. Carry on, chaps.
- Fievel! Fievel! Get in here with the family!
- Oh, I got... I gotta do something. I will be tough. I will be brave.
- It's a spy... A spee... A spide... De... De... De... An arachnid!
- Why, those no-good ornery varmints.
- Fievel, come back. Fievel! Fievel, my son, come back!
[...]