Sewer gas.
3 seconds sound clip from the Christmas Vacation (1989) movie soundboard.
You can hear this line at 01:32:10 in the Blu-ray version of the movie.
Quote context
[...]
- What?
- Santa Claus. No, it's the Christmas star. And that's all that matters tonight.
- Not bonuses or gifts or turkeys or trees.
- See, kids it means something different to everybody. Now I know what it means to me.
- That ain't the frigging Christmas star. It's a light on the sewage treatment plant.
- Oh, say does that star-spangled banner yet wave o'er the land of the free and the home of the brave?
[...]