Liquid sand? Ehhh maybe not.
However, thanks to a process called fluizidation, something as simple as pumping a constant flow of air through sand can make it act somewhat like a liquid.
As the air rushes between the individual sand granules, it reduces the friction between them, allowing for that smooth and silky behaviour. It means that you can run your hands through it and even float or sink objects like they would in actual water.
It does require getting the correct type of sand, as sand that is too course may not benefit from the stream of air due to the already large air spaces between the granules, or sand that is too powdery.
Is this possible on a large scale? Maybe? However, I wouldn’t want to be around to enjoy it as my lungs won’t like it that much.