This shit is the coolest fucking thing ever. Hans Reichel, a German musician, invented this instrument called a daxophone, which can be compared to the singing saw in the way that you have a 'tongue' (as it's called) that you bow and then amplify. The tongues can be shaped in all kinds of different ways for different overtones and soundscapes.
In the video picture you can see some of them. I fucking love this instrument, it's crazy how similar to the human voice it sounds at times.