I have been hoping for video of one of these for ages! It is a pellet bow, rare but found all over the world and especially in south east Asia. It is mostly used for shooting birds. Since it uses elastic force to store and release energy to propel a stone or clay ball, it is a true slingshot.
You twist the handle of the bow in your hand as you draw and this adds enough sideways force to the draw to make the stone miss the bow.
Note the doubled bowstring with the pouch in between like a hammock. There are small wooden separators to keep the bowstrings apart.