Moves
Quiver Dance and Iron Defense allow Dustox to bolster both its special and physical defenses, in theory enabling it to amass boosts while periodically recovering health and to eventually sweep with Bug Buzz. Bug Buzz is the strongest STAB move available, chosen over Sludge Bomb because that way only rare Soundproof users wall Dustox rather than all Steel-types. Roost keeps Dustox healthy, allowing it to heal off residual damage and continue to set up.
Set Details
Black Sludge provides passive recovery, letting Dustox boost more frequently instead of being forced to Roost. Shield Dust allows it to set up on weak or resisted attacks such as Scald, Body Slam, and Discharge, without fearing their crippling secondary effects. This means that, unlike most setup sweepers, Dustox takes advantage of passive, defensive Pokemon rather than being threatened by them. With the given EVs and a Calm nature, Dustox outspeeds Zebstrika, Floatzel, Jumpluff, and most other non-Choice Scarf Pokemon at +2 Speed while retaining as much bulk as possible to set up on special attackers.
Usage Tips
Dustox poses virtually no threat to a well-built team early-game, so it should only be used as a pivot until its checks and counters are extremely weakened or removed. It is pointless, and sometimes dangerous, to attempt a sweep while there are still phazers or healthy wallbreakers on the opposing team. Roost should be used frequently, as being at high HP minimizes the chance of falling to a critical hit. Dustox is not able to beat strong attackers without multiple boosts, so it should only be brought in on defensive Pokemon or after a teammate has fainted. Dustox should also not be switched in frequently, as entry hazards can quickly wear it down without the opportunity to Roost. However, its typing, at least, lets it switch in easily on Roselia and Tangela thanks to its 4x resistance to Grass. Unless Dustox is sent in on a physical attacker, Quiver Dance is the optimal opening move. The ensuing +1 Speed should allow Dustox to choose which defensive stat to boost next according to the Pokemon switched in.
Team Options
Dustox works best on defensive or balanced teams, as it can possibly sweep, absorbs Toxic Spikes, and can easily take otherwise frustrating moves like Scald. It is very hard to find an excuse to use it on offensive teams because it is extremely passive and drains momentum quickly, giving a free switch in to many threatening Pokemon. Even so, strong wallbreakers such as Stoutland and Simipour can aid Dustox with their ability to break holes in the opposing team. With Stealth Rock taking 1/4 of its HP upon switching in, as well as Spikes wearing it down, Dustox does not appreciate entry hazards on its side of the field. Worthwhile teammates that provide hazard removal and type synergy include Pelipper, Cryogonal, and Vibrava. It can often force switches against defensive Pokemon, so Pokemon that set up entry hazards make for good teammates. Most Rock- and Steel-types can use Stealth Rock and compensate for Dustox's vulnerability to strong Flying- and Normal-type attacks. Steel-types such as Probopass take on Jumpluff, while Rock-types ward off Rapidash and other Fire-type attackers. These Pokemon also appreciate Dustox absorbing Fighting-type attacks. While Dustox is immune to status as the secondary effect of an attacking move, Thunder Wave, Will-O-Wisp, and Sleep Powder give it trouble. Therefore, Pokemon that can absorb status, such as Clefairy and Pokemon with Heal Bell, such as Audino, make for excellent teammates.