[TOMT] Movie trailer where kid sings really creepy version of nursery rhyme [film]

Sorry there's so little to go on, but this is all i remember:

It's (obviously) a horror movie of some sort. The trailer doesn't show much -- maybe flashes of scenes from the movie? (just a guess) -- but whatever it's showing is accompanied by a kid singing a really creepy version of a kid's song/nursery rhyme. (Something like Twinkle Twinkle Little Star or Rock-a-bye Baby or something like that.) May have been thunder and lightning accompanying it as well.

Sorry so vague. Any ideas?