Hi, how do I reproduce this sound? What's the instrument? And the technique -- is it a reverse sound? A very slow attack?

UPD: https://vocaroo.com/1j3dkGq7mahD
I just tried this with a chord using a midi organ, with a slow attack, and sounds similar. Guess just need a different instrument, must be some synth.

the one that goes shka-shka-shka