Moves
Rock Polish is Sandygast's main move, as it allows Sandygast to outspeed the entire unboosted metagame after a boost. Earth Power is one of Sandygast's STAB moves, hitting Steel-, Rock-, and Fire-types such as Magnemite, Onix, and Ponyta. Shadow Ball is Sandygast's other powerful STAB move, hitting Psychic- and Ghost-types such as Natu and Gastly for super effective damage. Destiny Bond can be used to take down Staryu and non-Choice Scarf Pawniard along with other Pokemon that would be a threat to Sandygast's team, although it is best used after Rock Polish has been used and Sandygast has been weakened to the point where it can be easily OHKOed.
Set Details
Sandygast's EV spread along with a Modest nature allows it to hit as hard as possible with its two STAB moves and outspeed the entire unboosted metagame after it uses Rock Polish. The HP and Special Defense EVs allow Sandygast to almost always survive one Scald from Staryu. Berry Juice allows Sandygast to recover health so it can proceed to sweep with its powerful moves and Rock Polish; it also allows Sandygast to spinblock and take down Staryu efficiently. Water Compaction is the best choice out of Sandygast's two abilities, but it is a mediocre ability overall since Sandygast generally shouldn't switch into Water-type moves regardless of its ability.
Usage Tips
Sandygast's main purpose is to spinblock and take down Staryu, which is one of the most powerful and effective spinners in LC. Sandygast's EV spread allows it to take a Scald from Staryu most of the time, recover its HP with Berry Juice, and set up with Rock Polish to outspeed Staryu. Sandygast can then proceed to use Destiny Bond and take Staryu down with it. This should only be done if maintaining entry hazards on the opponent's side of the field is important for your team. Sandygast has a nice niche in being able to spinblock common spinners such as Drilbur and Staryu while being able to prevent Volt Switch from Pokemon like Magnemite. After all Flying- and Dark-type Pokemon have been eliminated, Sandygast can proceed to spam its STAB moves after it sets up; however, it still needs to beware of its remaining checks. In addition to beating Staryu, Sandygast can use Destiny Bond to take down other threatening Pokemon such as non-Choice Scarf Pawniard, but it needs to set up with Rock Polish to effectively utilize Destiny Bond. Slow VoltTurn support allows Sandygast to set up more easily because Sandygast struggles to take hits as a result of its low bulk.
Team Options
Due to its low bulk and its requirement to set up before being useful, Sandygast needs a lot of support from its teammates. Pokemon that resist Dark-type moves such as Pawniard and Vullaby make good teammates. Fighting-type Pokemon or priority users such as Timburr and Croagunk can deal with Pawniard and Fairy-type Pokemon such as Snubbull can deal with Vullaby. Onix, Chinchou, Magnemite, and Alolan Sandshrew make good teammates because they can take down the Normal / Flying types that wall Sandygast; Magnemite in particular appreciates Sandygast's ability to switch into Fighting-type moves while the former can tank most moves aimed at Sandygast, giving them good defensive synergy. Flying-types such as Rufflet and Vullaby are also good teammates because they can deal with Grass-type Pokemon such as Snivy and Cottonee that check Sandygast. Furthermore, Sandygast can take out most Rock-, Steel-, and Electric-types that trouble most Flying-types with Earth Power. Although they don't provide much defensive synergy, Fire-type Pokemon such as Ponyta and Larvesta can also deal with Grass-, Steel-, and Ice-types such as Snivy, Pawniard, and Alolan Sandshrew. Entry hazards allow Sandygast to sweep more easily as they break Sturdy and Focus Sash. Rock-type Pokemon such as Onix and Archen can help take care of Flying-types for Sandygast and can also set entry hazards to aid Sandygast's sweeping capabilities. In return, Sandygast can spinblock and take care of most Steel-types and spinners. Slow U-turn and Volt Switch users such as non-Choice Scarf Chinchou and Larvesta can help bring Sandygast safely.
