I should've known you'd ruin my fun, you big fat spoilsport.
4 seconds sound clip from Darkwing Duck - Toys Czar Us (S1E32).
You can hear this line at 00:05:02.202 in the DVD version of the TV Series.
Quote context
[...]
- Get ready for the Industrial Revolution!
- I am the terror that flaps in the night.
- I am the check writer in the cash-only line.
- I am obviously all out of my trademark blue smoke.
- I should've known you'd ruin my fun, you big fat spoilsport.
- I'll be back, Darkwing Duck.
[...]