I woke up and went to the bathroom, hearing a high pitched squealing coming from the living room. Upon investigation the sound seemed to be coming from nowhere in particular...moving toward and away from the source to test frequency distortion didn't seem to yield accurate results, because it turned out the mutilated furby on one of the tv trays was making an even higher pitched noise and that somehow is creating the sensation of this other lower (but still squealing) frequency permeating the room.
I put it in my camera bag and that seems to have dealt with the sound (I don't want to turn it off!) and now I have a bag of sound-
When I open it the room fills with a very high pitched squealing of indeterminate source. I'll have to test it outside at some point to see if the same effect can be observed.