http://www.smogon.com/bw/pokemon/slowking
The original skeleton was created by Honko, so please give him credit for that. Also, this is my first analysis; please bear with me and correct anything that is factually wrong or needs to be expanded upon. Thank you in return.
GP Checks: V0x (1 / 2), Snorlaxe (2 / 2)
[Overview]
<p>Slowking is a mediocre tank in the UU environment, despite sharing similar stats with the more popular Slowbro, since there are not many Pokemon Slowking can check that Slowbro cannot. Slowking is weak to some common special attacking types, such as Grass- and Electric-types. This means that even with maximum EVs in Special Defense and HP, and a positive nature, many common special attacks will 2HKO him. His physical Defense is somewhat lacking, inviting mixed attackers to walk all over him. However, Slowking can occupy a few niches. He can counter hail teams well, taking boosted Blizzards with ease, and is not worried by its residual damage. Access to recovery methods such as Slack Off and Regenerator ensure that he can continue to switch in on attacks without much trouble. Slowking's mediocrity as a tank may limit his presence in UU, but his services are not to be ignored.</p>
[SET]
name: Defensive
move 1: Scald
move 2: Psychic / Flamethrower
move 3: Slack Off
move 4: Dragon Tail / Thunder Wave / Toxic
item: Leftovers
ability: Regenerator
nature: Calm
evs: 252 HP / 120 Def / 136 SpD
[SET COMMENTS]
<p>Slowking's defensive set is a good check to Blizzard spammers, and is a solid switch-in to threats such as Choice Scarf Abomasnow, Choice Specs or Rain Dance Kingdra, Calm Mind Cobalion, and Agility Empoleon. He even has enough physical bulk to pose as a road block to Donphan, Hitmontop, Choice Scarf Mamoswine, and Arcanine without Wild Charge. Scald is a solid STAB move that can burn physical attackers, helping Slowking to take on such threats. Psychic blows Fighting-types, most notably Hitmontop, to pieces. Flamethrower, however, deals with Abomasnow, which can threaten Slowking with Wood Hammer. Slack Off is an incredibly useful move, as it restores 50% of Slowking's HP in one turn. Finally, Dragon Tail is a useful phazing move, and can stop set-up sweepers. When phazing is not required, Slowking can fall back on two status options: Thunder Wave and Toxic. Evidently, Slowking is unable to outpace anything, and Thunder Wave can resolve this. Ground-types are not an issue, as they are hit for super effective damage by Scald, which further cements Thunder Wave as an option. Toxic, however, puts great pressure on the opposition, making it a good choice as well.</p>
[ADDITIONAL COMMENTS]
<p>Slowking's EV spread and nature allows it to survive 164 Atk Abomasnow's Wood Hammer, and absorb a Life Orb Modest Chandelure's Shadow Ball. Leftovers is the item of choice to gradually regain HP every turn. Regenerator is an excellent ability on a set like this, as it allows Slowking to regain one-third of its HP simply by switching out, ensuring that repeated attacks and entry hazards do not wear it down.</p>
<p>Teammates for Slowking are those that can take advantage of Slowking's ability to absorb Blizzards and other moves that hit Slowking's teammates super effectively, but not Slowking itself. They include slow Dragon-types, such as Druddigon and Shelgon, which are vulnerable to Blizzards from faster Pokemon, and defensive Grass-types, such as Tangrowth and Shaymin, which take Grass- and Electric-type attacks for Slowking, while Slowking switches in on Ice-, and Fire-type attacks. Slowking can also check Calm Mind Cobalion, Rain Dance and Choice Specs Kingdra, and Agility Empoleon well; Pokemon that have trouble with the aforementioned threats, such as Nasty Plot Houndoom, can pair up with Slowking to perform more efficiently.</p>
[SET]
name: Trick Room
move 1: Trick Room
move 2: Surf
move 3: Psyshock / Psychic
move 4: Ice Beam / Fire Blast / Nasty Plot
item: Life Orb
ability: Regenerator
nature: Quiet
evs: 252 HP / 252 SpA / 4 SpD
ivs: 0 Spe
[SET COMMENTS]
<p>With Trick Room, Slowking can step outside of a defensive role and fire off attacks right away. Thanks to Regenerator, Slowking can set up Trick Room multiple times throughout a match. His Special Attack and movepool are also decent enough to fire off attacks and cover certain threats. Surf is the first option on a Trick Room set for Slowking, as it packs solid power, STAB, and perfect accuracy. Psyshock and Psychic serve as secondary STABs; Psyshock hits Chansey on its weaker Defense, while Psychic has a higher Base Power. Ice Beam and Fire Blast round out the set's coverage. Ice Beam freezes Grass- and Flying-types, and Fire Blast burns Abomasnow and other Ice-types to a crisp. Finally, Nasty Plot is an option to double Slowking's damage output.</p>
[ADDITIONAL COMMENTS]
<p>Slowking's EV spread is a standard sweeper spread optimized for Trick Room; 252 Special Attack EVs allow Slowking to deal maximum damage, 252 HP EVs provide added bulk, and the remainder are put into Special Defense. The Speed IVs are set to 0 to reduce Slowking's Speed, and a Quiet nature is chosen to bump up Slowking's Special Attack while reducing its Speed further, allowing Slowking to outspeed more Pokemon in Trick Room. Life Orb enables Slowking to dish out more damage.</p>
<p>As always, Slowking desires teammates that synergize well with it. Tangrowth absorbs Grass- and Electric-type moves for Slowking, and Slowking can switch in on Fire- and Ice-type moves that Tangrowth lures. They also take physical and special attacks for each other, and benefit from Trick Room. Hitmontop takes little damage from the Bug-type moves that Slowking and Tangrowth attract. Hitmontop is somewhat fast for Trick Room, but his defensive ability should not be ignored. Offensive partners are those that make use of their low Speed stat to abuse Trick Room, such as the aforementioned Tangrowth and Druddigon.</p>
[Other Options]
<p>Slowking has a versatile movepool, but most of it is left to waste, usually because they are inferior to other moves. Those moves are Grass Knot, which uses up a moveslot since Psychic or Psyshock can hit bulky Water-types just as hard; Focus Blast, which is inferior to Slowking's Fire-type attack due to low accuracy; Shadow Ball, which has little coverage with Slowking's other moves; Signal Beam, which is underpowered compared to Slowking's Fire-type attack; Calm Mind, which is inferior to Nasty Plot since Slowking already has great Special Defense; Curse, which is terrible with Slowking's low Attack; Rain Dance, which is better left to Kingdra; Yawn and Disable, which use up a moveslot to be effective; and Wonder Room, which has a useless effect.</p>
[Checks and Counters]
<p>Roserade and Celebi can hurt Slowking with a super effective STAB Leaf Storm or Giga Drain. STAB Megahorn from Heracross hits Slowking hard. Zapdos, Raikou, and Jolteon all strike Slowking for super effective damage with STAB Thunderbolt. Mismagius and Mew hit Slowking for super effective damage with Shadow Ball. Finally, Azelf can utilize Grass Knot or Thunderbolt to hurt Slowking. Status effects also hinder Slowking; Toxic is particularly devastating.</p>