Serperior
Dex Number: #497
Type: Grass
Base Stats: 75/75/95/75/95/113
Abilities: Overgrow Hidden:
Contrary
Notable Moves:
Level up:
Growth
Leech Seed
Coil
Leaf Blade
Giga Drain
Leaf Storm
Gastro Acid
Egg moves:
Glare
Mirror Coat
TM moves:
Calm Mind
Hidden Power
Light Screen
Reflect
Dragon Tail
Swords Dance
Substitute
Taunt
Tutor Moves:
Aqua Tail
Dragon Pulse
Knock Off
Outrage
Synthesis
Overall Analysis
Serperior, ever since it was released as the starter grass final evo, was rather quickly dumped into the depths of NU, seemingly never to rise again, with its subpar offenses, somewhat salvageable defenses and good speed. The main things it could do in NU were set up screens and seed stuff, set up coils and attempt to be bulky, or go on the offensive with calm mind+life orb shenanigans.
However, it was announced that serperior was to get the amazing hidden ability contrary, which reverses any stat changes this pokemon experiences. As soon as this was announced, players set their eyes on one move: LEAF STORM. This amazingly powerful 140 bp move (now 130) was not only STAB and hit decently hard, it DOUBLED serperior's special attack after the first use. From there, it was +4, and +6, and before long, serperior would be a gigantic threat to contend with.
Of course, Troll Freak does what it does best, and they never actually released contrary serperior in gen 5, along with a couple of other hidden abilities people were waiting for, like shadow tag chandelure. However, in gen 6, contrary serperior is perfectly legal, and even though our awaited ability was born into a much harsher world, contrary serperior will still prove to be a huge threat.
With its solid 113 base speed and a STAB 130bp boosting move, XY will grant the wish of our little green snake and make it something to watch out for.
Potential Sets
Life Orb
Serperior@Life Orb
Nature: Timid
Ability: Contrary
EVs: 252 sp. att/252 spe/4 sp. def
-Leaf Storm
-Hp Fire/Rock/Ice
-Dragon Pulse
-Giga Drain/Taunt
This set aims to outspeed common pokemon in the tier and attempt to damage the opponents team by throwing around leaf storms. It works sort of like a celebi, but with better speed and not having to waste a move slot for nasty plot, its much more of a threat. Celebi has its merits though, it baton pass the nasty plot boost to someone else. There are 2 things that make serperior shine with this set: Talonflame are everywhere in the new OU metagame, and its no surprise to see why. Thus, Rotom-W has come out as the premier check to talonflame and whatever it wants to do. Rotom-W has the most trouble with grass types, and is basically set up fodder for this serperior. Unless your opponent predicts your serperior switch in and volt-switches, this thing is a really nice check to Rotom-W. The switch in, commonly a steel type like aegislash, skarmory, or mawile, can take the leaf storm, but die the +2 Hp fire (which is more or less the hidden power you should be running) Dragon Pulse is there as the strongest coverage move you have, and helps out with AV Goodra.
The second reason serperior is pretty cool is that it doesn't have a dark/ghost weakness. All the common grass types of this tier suffer from this (celebi, trevenant, gourgeist), but serperior doesn't have to worry about this at all.
Giga Drain is there to give you some health back, as when you switch into rotom-w and take a will-o-wisp (happens often), you will be losing health quickly with life orb. Giga Drain is just there to keep your health at a respectable amount.
4 evs in sp. def just there to ensure incoming genesect get the attack boost instead
Taunt is a decent option if you want to break through chansey/blissey/gliscor easier.
It's also worth noting that 113 speed sets serperior in a good speed tier, just 1 point above mega lucario, and with 113, you're outspeeding a good portion of the mega evolutions as well.
Choice
Serperior@Choice Scarf/Choice Specs
Ability: Contrary
Nature: Timid
Evs: 252 sp. att/252 Spe/ 4 Sp. def
-Leaf Storm
-Hp Fire
-Dragon Pulse
-Giga Drain/Filler
This set isn't too different from the life orb one, but works a little differently. The crux of the scarf set is (you guessed it!) leaf storm, and the general idea is to work like a moxie salamence, but boosting leaf storm's instead of say, outrages. Honestly, you don't even need these 3 other moveslots for this serperior to do what it needs to do, but for formality's sake, lets include them. With a timid scarf serperior, you're cleanly out speeding the entire unboosted metagame. It's worth noting that if your opponent doesn't catch on, this thing is pretty great bait for genesect with HP fire.
The specs set, however, is completely different, functioning as a wallbreaker capable of breaking through chanseys, blisseys, gliscors, jellicents, and rotom-wash's alike. A specs leaf storm will hurt, but this thing will be even stronger, instead of becoming set up fodder like common specs dragons w/draco meteor.
Support
Serperior@Leftovers
Ability: Contrary/Overgrow
Nature: Timid
Evs: 252 HP/252 Spe/4 Sp. def
-Light Screen/Substitute
-Reflect/Leech Seed
-Dragon Tail/Giga Drain
-Taunt/Knock Off/Glare/Gastro Acid
The calm green snake, despite having amazing offensive potential with contrary, has an outstanding support movepool. The main things serperior can do with this is set up screens or go subseed. Admittedly, there are much better subseeders and dual screeners in the OU tier, but serperior does even more than that. It boasts moves like taunt, knock off, glare, and even gastro acid, many of which better subseeders cannot do. It has a combination of very good speed and 95 base defenses, something which standard sub seeders like trevenant and gourgeist do not have. Overall, this thing is outclassed by a lot of other things, but its a mixed bag which can work to your advantage if used properly.
Checks and Counters:
Talonflame. Serperior cannot hold a damn candle to talonflame in anyway possible. Talonflame outspeeds, walls, and promptly kills any serperior, and basically every other grass type out there. Completely walling the life orb and specs sets is difficult simply because of the +2 boost after every leaf storm, but its much easier to outspeed and kill. The scarf set, on the other hand, is easier to wall with things like sap sipper goodra (or any sap sipper pokemon for that matter) and toxicroak, to name a few. Sawsbuck deserves special mention simply because it can come in, get the sap sipper boost, and proceed to smack the switch in with a boosted attack (but sawsbuck loses out on earthquake now that nature power turns into tri attack). Scolipede and Blaziken can come in to revenge kill, but be aware that serperior is still faster while unboosted, so you have to protect to outspeed. Switching directly in may cost you a lot health (and a dead scolipede if hp fire), so play carefully around a boosted serperior.
Several steel types can come in and threaten serperior out with powerful attacks, such as mawile and aegislash, but only on the choiced sets, as the aforementioned pokemon will swiftly be taken out by a +2 hp fire. Mamoswine is a decent check as his ice shard (LO) does a solid 60-70%. Heatran also takes basically everything serperior has to offer, a complete stop. Can proceed to Fire Blast if offensive or Roar if defensive. Mega Venusaur takes less than 30% even from +2 HP fire, and dragon pulse won't be doing much more. It can then proceed to sludge bomb and kill.
Other Options
Serperior can attempt to go physical with swords dance and coil, but the coil set is outclassed by zygarde, who has extremespeed, and there are about 20 different swords dancers that could get more accomplished than serperior. Remember, you're working off of a 75 base attack stat that you can't boost simply by spamming a STAB move. As far as physical options go, it gets seed bomb, outrage, pursuit, iron tail, and aqua tail, but really, don't go physical with serperior. Please.
On another note, you could attempt to go a sun sweeper as serperior has synthesis, growth, and leaf storm, but why you'd be using this over venusaur, I don't know.
In doubles, you can use grass pledge with water pledge to create a marsh that lowers the opposing team's speed to 1/2. All the pledge moves also got boosted to 80 bp instead of 50, so there's that. Why you'd bother using this over tailwind or sticky web, I don't know, but it deserves a mention.
Teammates
Talonflame gets a special mention as serperior gets rid of rotom-w and basically every other bulky water stopping our little phoenix. To summarize, if your sweeper wants a bulky water gone, serperior is a good option. Serperior itself, however, needs things like scolipede, talonflame, and blaziken gone to survive, so a bulky water, like rotom-w (He's a big part of the metagame huh) is appreciated to take on these threats. A powerful ground type, like garchomp, can benefit from dead rotom-washes, and in return, garchomp can kill heatrans and other steel types serperior cannot get through.
Conclusion/Personal Opinion
This thing is underwhelming at first, but if you let it set up, I believe it can sweep teams very nicely. A +2 boost every time you use STAB leaf storm, the strongest viable grass type move, is no joke. A lot of pokemon get stopped by bulky waters like tentacruel (azumarill), rotom-w (talonflame), and Gyrados (misc.), and serperior is in my opinion the best offensive grass type pokemon to clear them out (other than shaymin-s, but he's ubers). A combination of 113 base speed, which outspeeds a good portion of megas, solid 75/95/95 defenses, and a tier teeming with rotom-washes at every damn corner, serperior will find a solid throne in OU like he should've in 5th gen.