Moves
Sticky Web slows down the opponent's grounded Pokemon, giving powerful teammates such as Magmortar and Aurorus the advantage in Speed. Leaf Storm is Leavanny's main weapon, demolishing common entry hazard removers such as Kabutops, Prinplup, Claydol, and Sandslash, as well as pummeling various Stealth Rock users such as Rhydon, Piloswine, and Carracosta. Electroweb is an important move for Leavanny, as its Speed drop grants Leavanny more flexibility as a lead. Electroweb lets Leavanny gain the advantage against faster Taunt users such as Archeops and Mismagius, allowing Leavanny to properly decide its next course of action depending on the foe's move without wasting any precious turns. Electroweb also deals some chip damage against faster foes while still allowing Leavanny to set up Sticky Web, as well as slow down foes that have not been affected by Sticky Web for its teammates. Bug Buzz gives Leavanny an additional STAB move and is Leavanny's best weapon against Xatu, especially if boosted by Swarm, while also striking down Mesprit, Torterra, Lilligant, and Shiftry, which may try to set up or use Defog. More importantly, Bug Buzz provides the team insurance against Malamar, which may try to take advantage of Sticky Web with Contrary and pull off a sweep.
Magic Coat is a possible alternative to prevent Leavanny from being Taunted outright and allow it to set up Sticky Web, and it is notably useful against defensive Mawile by reflecting back Stealth Rock and Taunt. Magic Coat can also reflect back Spikes and Lovely Kiss from the likes of Garbodor, Roselia, and Jynx, but it would be risky to attempt Magic Coat against these foes due to their super effective STAB moves. Magic Coat also requires stellar prediction and has the potential to do nothing, whereas Electroweb also already makes a fine response against the faster Taunt users and is much safer to use.
Set Details
Maximum Speed investment and a Timid nature allow Leavanny to outspeed as much as possible, maximizing its chances to set up Sticky Web even without its Focus Sash intact. It also allows Leavanny to outspeed uninvested +1 Malamar, which Leavanny can proceed to KO with Bug Buzz. Maximum Special Attack investment allows Leavanny to dish out the most damage possible, which is important, as its time on the field is short. Focus Sash allows Leavanny to survive any one hit from faster foes. Swarm gives a significant boost to Bug Buzz, which can overwhelm Xatu, but Overcoat is a possible alternative to prevent hail or sand from rendering Leavanny's Focus Sash useless, although neither weather condition is very common.
Usage Tips
Setting up Sticky Web should be Leavanny's main priority. However, Leavanny does not necessarily have to lead, as its Speed usually allows it to set up Sticky Web on at least one of the opponent's Pokemon. Because of this, Leavanny can afford to hold off on setting up Sticky Web if it can threaten a KO on a slower Pokemon, namely a Rock-, Water-, or Ground-type, and if the opponent has other slower Pokemon available that can give Leavanny additional opportunities to set up Sticky Web. Should Leavanny, with its Focus Sash intact, face a faster foe, it should use Electroweb before setting up Sticky Web to both deal chip damage and slow down the foe for its teammates; however, this strategy is not advised if the foe has access to any priority moves besides Sucker Punch. Leavanny should exercise caution if Xatu is present on the opponent's team, as Sticky Web can be bounced back via a timely Xatu switch in. Leavanny should hit Xatu on the switch with either Electroweb or Bug Buzz in order to prompt it to use Roost, giving Leavanny's teammates a free switch into it. While it isn't advised to preserve Leavanny, it can be saved for the late-game, as it can launch strong and fast attacks of its own and act as insurance against Malamar.
Team Options
Leavanny only really fits on offensive teams, as they best take advantage of the opposing team's decreased Speed and punish any attempts to use Rapid Spin or Defog with powerful blows. Spinblockers prevent Rapid Spin from clearing Sticky Web, making them useful partners; Misdreavus makes for a reliable bulky spinblocker that can make decent use of Sticky Web with access to Taunt and Will-O-Wisp, Rotom is a more offensive spinblocker that can deal with Flying-types, which are immune to Sticky Web, and Golurk is an offensive powerhouse that is more than capable of making use of Sticky Web. Fighting-types, such as Hitmonchan and Primeape, can punch through slowed foes with little trouble while providing insurance against Pawniard, which is a threat against Sticky Web teams due to Defiant, by virtue of their resistance to Sucker Punch; Primeape even has Defiant as a bonus to take advantage of the opponent's Defog users. Malamar, Servine, and Pawniard make opposing Xatu's attempts at bouncing back Leavanny's Sticky Web fruitless, as the Contrary users will receive a boost in Speed and outrun foes, while Pawniard trades Speed for a +2 Attack boost, which is incredibly useful when using Sucker Punch.
Powerful attackers in general highly appreciate Sticky Web support; the likes of Magmortar, Jynx, Aurorus, Kabutops, Zangoose, Kangaskhan, and Mawile gain a wider range of targets that they can now plow through. It is advisable to have teammates that can counter Flying-types and Levitate users, most of which pack great offensive presence of their own and are immune to Sticky Web; Rhydon, Piloswine, Aurorus, and Kabutops make for decent stops against Flying-types, while priority moves can also help to keep both Flying-types and Levitate users in check. Alternatively, equipping a Choice Scarf on the likes of Jynx and Rotom can also help combat airborne Pokemon. Rapid Spin users such as Kabutops and Sandslash can get rid of entry hazards for Leavanny should it not want to lead but still intend to keep its Focus Sash intact, but this isn't particularly necessary.
