He sees you when you're sleepin'. He knows when you're awake.
5 seconds sound clip from the Shrek the Halls movie soundboard.
You can hear this line at 00:00:48 in the Blu-ray version of the movie.
Quote context
[...]
- He sees you when you're sleepin'. He knows when you're awake.
- What are you doing here, Donkey? And what are you talking about?
- I'd better be good? How 'bout this? You better be scarce. Now go on. I don't care about Christmas.
- Jingle bells, jingle bells, jingle all the way.
- There's only 51 days left till Christmas.
[...]