In the Saw movies, a laughing noise was played whenever Billy the Puppet appeared. You can hear the laughing noise repeated several times in this video. Is that noise an artificially created sound effect, or did they record an animal making that noise?
Very late, sorry. I too am interested in finding the source because I recall my grandmother owning a bat Halloween prop that would hang over the door way and when you hit it it would shake and make a similar sound source. Anyways I found this video which is kind of like what my grandmother had except it wasn't a pumpkin and was covered with felt. -
I'm going to say it's a created sound effect. I've fairly exhaustively searched online and I can find nothing about who created it. I'm of the mind that that's because it was too commonplace to credit. It's a simple thing to create and many similar laugh sounds can be found (for free) across the Internet.
So I'm saying - artificially created sound effect. I don't think a definitive answer will ever be given for this question, unless one of the production team happened to comment.