The Creepy Noise Made by the Mother Ghost in "The Grudge"

It has been in my head all week. As I sit here @ home, alone, working, I can hear it in the background. I am sure it is just the janitorial staff, vaccuuming, but it could be something else. Something much more cruel, some nasty, decaying creature, trying to find its way into our world to destroy mankind, or find one last victim before retiring. Could that be me? Stupid movie.