Best evil singing of a 'nice' song in a movie?

[Queasy]

What's the best evil singing of a 'nice' song in a movie? You know, one that just creeps you out or something.

Example:

HAL in 2001: A Space Odyssey
"Daisy." Daisy, Daisy, give me your answer do. I'm half crazy all for the love of you. It won't be a stylish marriage, I can't afford a carriage. But you'll look sweet upon the seat of a bicycle built for two."

That always creeped me out.

 

[Ness]

I'm guessing there are only a few entries in this category.

 

[Biggerhammer]

"Man from La Mancha"
Song: "Little Bird"

It's worse because they sing it as a fun little song first, then go and gang-rape Dulcinea while they sing it the second time.

 

[newbiepcuser]

"Time is on my side.....oh yes it is"-Fallen with Denzel Washington

 

[veggiefrog]

those sisters in the shining that chant 'forever and ever and ever...' over and over again freak my bf out.....

 

[hdeck]

on an opposite spectrum, the old 30s style singing of disturbed's "down with the sickness" in dawn of the dead was just creepy.