Sandstorm's name is Conjectural. No official name has been given, and it is subject to change at any time.
Sandstorm was the unnamed Quirk possessed by Snatch.
Sajin's Quirk gave him the ability to transform his upper body into sand.
Sajin could manipulate this sand freely, allowing him to shape it into different forms.
Sajin could attack, defend, and restrain opponents using his sand-transformed limbs. Sajin was skilled enough to even repel flames by swinging his sand around.
This Quirk gave Sajin an advantage against certain contact-requiring Quirks like Decay. Sajin's fluid upper body made it nearly impossible for someone to get a grip on him, although it didn't provide protection from area-hitting abilities like Compress.