Dispersal. As a bonus action, the sand assassin can disperse or end its dispersal. While dispersed, the sand assassin is Gargantuan, its space is lightly obscured, enemies have disadvantage on attack rolls against it, and it is indistinguishable from a cloud of dust, but it cannot make attacks and it automatically fails all Strength saving throws and ability checks.

Sand Form. The sand assassin can move through a space as narrow as 1 inch wide without squeezing. In addition, the sand assassin can enter a hostile creature's space and stop there. The first time it enters a creature's space on a turn, that creature must succeed on a DC 14 Constitution saving throw. A creature that ends its turn inside the sand assassin's space must also make the saving throw.

On a failed saving throw, a creature is blinded for 1 minute. A creature repeats the saving throw at the end of each of its turns, ending the effect on a success.

Glass. If the sand assassin takes more than 15 fire damage at once, it partially glasses; its speed is reduced by 5 feet for 1 minute.

Undetectable in Sandstorms. While the sand assassin is heavily obscured by sand or dust, it is invisible and it can't be sensed by blindsight or tremorsense.

Multiattack. The sand assassin makes two Sand Claw attacks.

Sand Claw. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 18 (3d8 + 5) slashing damage. If the target does not have any allies within 5 feet of it, the sand swirls around it and the attack deals 9 (2d8) bonus slashing damage.