Vivillion

First of all, this needs a brief introduction. Contrary to what it may seem, I'm not writing an analysis about a cheesy pokémon just because this year I already have my Worlds invite and I don't care about doing well until then. On the contrary, now I have the occasion to study the metagame more calmly and all the possibilities it gives, and while Vivillion is undoubtedly an eccentric choice, I really think it can do it's job and that it's worth using it!

About Vivillion

Despite being another butterfly pokémon, Vivillion is basically a Butterfree with  more HP, Speed and better movepool.

Unfortunately with 80/50/50 defensive stats, Vivillion is not something the average player is able to employ to make a successful team, however it is by no means bad, it just needs some specific support in order to give it’s best.

Now you may be asking: “why should I waste my time building around this” , I hope to be able to answer you with the next paragraph.

Vivillion Niches:

- Sleep Powder: With the second of its three abilities, Compoundeyes, Vivillion gets, just like Butterfree and many other bug types, a 30% accuracy boost on its moves; and between all of them, the one it probably enjoys the most having this boost on is going to be Sleep Powder, which reaches a nice 97%, becoming almost as reliable as Spore (no secret here, this alone may be a good reason to use the moth, Spore and 89 base speed is not something to laugh at).

- Hurricane: Well, here’s where Vivillion outclasses its Compundeyes colleagues: it can deal actual damage! When in VGC13 players preferred Breloom to Butterfree and Venomoth as a Spore user, it was because the latters couldn’t really do worthy damage. But Vivillion is superior here, with a 91% accuracy STAB Hurricane that, combined with its decent 90 base SAtk  and a nice additional 30% chance to confuse the opponent.   

- Rage Powder: Needless to say what Rage Powder does, just that I think that redirecting attacks, basing on my experience, is one of the best things a pokémon can do in double battles.

Nevertheless, when using this move, you need to keep in mind that the priority is now reduced to +2 and watch out for grass types, whose attacks aren’t going to be redirected!

- This:

- Powder: Last but not least, Vivillion's signature move. A really interesting attack, having +1 priority and blocking an opponent trying to use a fire type move, while dealing damage equal to 25% of opponent’s HP. By the way this is something that works better with the surprise effect.

The Butterfly of this generation can be used as a check to one of the top tier Mega-Pokemon, nice!

- Friend Guard (Trait): I don’t feel like telling much here since I don’t have any experience using that on this pokèmon, and I still think that the best user of the ability right now is Jigglypuff.

Even so, it still needs to be mentioned, because it’s a very rare ability (owned by only three evolutionary lines) and can be an useful support for many teams (always keeping in mind that as you  choose Friend Guard, Sleep Powder and Hurricane both once again become unreliable attacks). 

Inferior options: It needs to be mentioned that Vivillion also gets Safeguard, String Shot (yeah, I know some people that would actually use it!) and Quiver Dance.

A Set Example

Vivillion @ Focus Sash

Trait: Tinted Lens

EVs: 4HP / 252 SAtk /252 Spe

Modest Nature (+SAtk, -Atk)

-Sleep Powder

-Hurricane

-Bug Buzz

-Protect/Rage Powder/Safeguard

With this EV spread it can get the OHKO on 4/0 Venusaur so, if given the right support, like tailwind Aerodactyl for example, it can be a half of an anti Venu-Zard combo; While Being maintaining a 141 Speed stat. which is right enough to outspeed max speed positive Mega-Heracross, the raising-in-popularity Florges with 252 EVs and a positive nature too, and most notably, maxspeed positive Smeargle.

The focus sash is put there for repair to Vivillion’s awful defences, but if you feel like getting the ko on 4/0 Venusaur isn’t enough (and you’d be probably right) you can swap the Sash with an offensive Item (adjusting the EV spread basing on your team needs).

Good pokèmon to pair Vivillion with are those who can prevent the Sash from Breaking, like Politoed and Charizard Y and, if you’re planning to take on sun with it, good Charizard counters and checks for Venusaur’s Sleep Powder (one of them is just choosing Safeguard as Vivillion’s last move).

Little EV Spread Help 

Defense

70(0) à take a Sucker Punch from max Atk  Adamant Mega Kangaskhan and Bisharp

80(76) à Take a Rock Slide from Jolly max Attack  Garchomp after an Intimidate

99(228) à Take a Gyro Ball from Ray’s Ferrothorn (94% of the times) or a Rock Slide from an Intimidated Jolly max Atk Aerodactyl (82% of the times)

Special Attack

110(0) à OHKO 252/0 Malamar with Bug Buzz

120(76) à 2HKO 252/0 Mega Abomasnow with Bug Buzz

156(252+) à OHKO 4/0 Venusaur with Hurricane

Special Defense

86(128) à Take a Sludge Bomb from timid max special attack Mega Gengar

91(164) à Take a Draco Meteor from max SAtk Scarf Timid Salamence

97(212) à Take a Muddy Water from max SAtk Modest Life Orb Kingdra in the rain

Speed

125(124) à Outspeed Max Speed Tyranitar with a positive nature

141(252) à Outspeed max Speed Smeargle, Mega Heracross and Florges with a positive nature

154(244+) à Outspeed Base max speed 100s with a neutral Nature

- Arash