Calm Coffin
Cofagrigus@Leftovers
Bold nature
Mummy
252 HP/252 Def/4 Sp. Def
~Calm Mind
~Shadow Ball
~Hidden Power (Fighting)
~Protect/Will-O-Wisp
The perfect set to take full advantage of Cofagrigus's immense bulk. Max out the EVs for HP and Defense, and allow Calm Mind to handle the Special Defense. From there on, attempt a sweep with Shadow Ball and HP Fighting (flawless coverage). The last move is mainly filler. Protect allows for additional Leftovers recovery, and Will-O-Wisp helps with the physical bulk.
Item is obvious. Ability is non-negotiable.
Trick Tomb
Cofagrigus@Wise Glasses
Quiet nature
Mummy
252 HP/252 Sp. Atk/4 Sp. Def
~Trick Room
~Shadow Ball
~Hidden Power (Fighting)
~Energy Ball/Grass Knot
Cofagrigus's low Speed is the main thing that prevents it from becoming one of the great sweepers of our time. Well, OK, its movepool doesn't exactly help it out either. But, that first problem ceases to be problematic with a single use of Trick Room. Relying on Cofagrigus's natural bulk (and considerable HP EVS) to pull it off is no problem, and afterwards, a sweep is a breeze. Ghost/Fighting has perfect coverage, last move is filler.
Wise Glasses is obviously preferable over Choice Specs, and also over Life Orb. As Cofagrigus will likely take a heavy hit while setting Trick Room up, one can't exactly afford all that recoil. Ability is non-negotiable.
Nasty Burial Plot
Cofagrigus@Leftovers
Quiet nature
Mummy
252 HP/128 Def/128 Sp. Def
~Nasty Plot
~Shadow Ball
~Hidden Power (Fighting)
~Energy Ball/Grass Knot/Trick Room
This Cofagrigus, as opposed to the previous one, is made to take advantage of Trick Room, rather than set it up. Nasty Plot builds up its already nice Special Attack, Shadow Ball and HP Fighting allow you to sweep. Last move is filler. A Grass move allows you to hit stuff like Quagsire extra hard, whereas Trick Room means that when Trick Room runs out, Cofagrigus isn't dead meat (well, more dead than it already is, being a Ghost-type).
Make Way For The King!
Yamask@Ring Target
Bashful nature
Mummy
0 HP/0 Atk/0 Def/0 Sp. Atk/0 Sp. Def/0 Spd
~Curse
~Will-O-Wisp
~Astonish
~Disable
This set may seem like a complete and utter waste of team space, right? Not if another Pokémon on your team goes by the name of Slaking. The sole purpose of this Yamask is to be switched into a predicted physical contact move. Even a Normal or Fighting move would work, thanks to Ring Target. Bring in Yamask, the foe KOs it (this Yamask should be as low of a level as humanly possible, did I mention?), then you bring in Slaking. This all happens in the span of one turn, so the next turn, the foe's likely to figure out what you're trying to pull and will likely switch out. That's when Slaking goes for Pursuit. And acquires Mummy. In place of Truant. Done drooling now? OK. Oh, and the moves don't matter at all, as this Yamask isn't supposed to be actually doing anything. Hell, it could use Toxic, Telekinesis, Flash, and Dream Eater for all I care.
The item is to ensure that Yamask can receive a Normal or Fighting attack and activate Mummy. If the attack doesn't affect Yamask, Mummy won't activate. Ability is, as usual, non-negotiable. Not only that, it's the entire point.
Other options:
*Cofagrigus gets Haze, and has the stats to pull it off. Unfortunately, a lot of its sets involve moves that boost its own stats, so Haze would be a tad counterproductive. It might be useful on a set that focuses on special bulk with the EVs and runs Will-O-Wisp in place of Calm Mind, but it's rather situational.
*Power Share is a decent, if not gimmicky, means of alleviating Cofagrigus's horrible Attack stat. Only problem is, its physical movepool is equally horrible, consisting entirely of Payback, Astonish, Return, Frustration, Thief, Facade, and Giga Impact. Yeah. That right there is a list of every single physical move Cofagrigus gets.
*Memento is an option on the Yamask set, with Focus Sash replacing Ring Target, giving the foe even more of an incentive to switch out (and get hammered by Slaking's Pursuit). Unfortunately, this comes at the price of Normal and Fighting immunity.
Abilities:
*Mummy: Cofagrigus's one and only ability. If it takes a contact move, the foe's ability changes to Mummy. Useful for physical attackers that rely on their ability, like Haxorus. Extremely useful for ridding a fellow teammate of an unwanted ability, like Truant or Slow Start.
Partners:
Slaking. You want Slaking on the same team as Yamask. I have done this myself with fantastic results. For Cofagrigus, however, you're gonna want that thing to stay alive, so Wish support is appreciated, usually from the likes of Alomomola or Blissey. Of course, having a Slaking waiting in the wings doesn't hurt either. Regigigas also works in theory, but can't learn Pursuit.
Counters:
Anything with U-Turn is a big screw-you to Yamask. Cofagrigus has to be wary of big hitters like Tyranitar and Scrafty, but can cripple them with Will-O-Wisp (especially Scrafty, after its Shed Skin is taken over by Mummy). Snorlax, especially varieties that run Rest, will be immune to Shadow Ball, and its tremendous special bulk means that HP Fighting doesn't make as large a dent in Snorlax as said Snorlax would in a buffet.
Opinion:
The entire evolution line is just awesome, in looks, in stats, and especially Yamask's nice niche when paired with Slaking. Seriously. Do not underestimate that little combo. A Slaking without Truant will walk all over pretty much everything.
