https://www.youtube.com/watch?v=_aY6TxC1ojA

from the video description:

This is an acoustic instrument with no electricity or anything... Natural source coded materials which are membrane, coiled spring and string working together. Maybe we can say that this is a new bridge system between string and resonant body. But generally this is a new design and emit obviously natural vibrations and gives new playing abilities.
Very important that it has totally a unique live listening experience!!

it's basically an experimental acoustic instrument that someone made that sounds like a synthesizer. it's really fucking cool. i kinda want one of my own.