Here are the nitpicks! Overview -In the flaws part, I think you should also mention that Mewtwo's typing is pretty poor defensively, with only two resistances (Fighting and Psychic), which makes the bulk problem bigger when you don't invest. Psycho Killer -Ice Beam actually does more to Latias before it Calm Mind, Psystrike is more of a tool to beat it in Calm Mind wars so just remove the Latias mention there. -FYI, even max HP Dialga with no Special Defense investment isn't going to get OHKOed at full health by Aura Sphere (does 72.02 - 84.9%), so while its a heavy wound, I wouldn't call it "destroying" since Dialga can hit you pretty hard if it lives! You might want to also mention that Aura Sphere 2HKOs bulky Excadrill in the rain. -Ice Beam 2HKOs Giratina and Lugia. In Giratina's case, say Physically Defensive, because Specially Defensive isn't even 2HKOed by an unboosted Ice Beam! -Might want to mention that if you have sun support, you get some nice OHKOs vs Excadrill, Jirachi, and Steel Arceus! -For Calm Mind, you should mention how it allows you to bust through Giratina, Lugia, and max HP Arceus more easily. The last two are notable because if they switch into the right move, they can spam Roost / Recover to wear you down since Ice Beam and Psystrike respectively are not guarnteed 2HKOs without a boost. -For the Sunlight part, mention that using Fire Blast + Aura Sphere WILL make Giratina harder to beat with CM Mewtwo. Psycho Killer Additional Comments -A small plus for Shadow Ball is that it does a bit more to unboosted Ghost Arceus than Psystrike. -In the paragraph about items, get into more details about the power loss stuff. For example, you lose the 2HKO possibilities vs Max HP Arceus, Lugia, and Physically defensive Giratina. Also in Leftover's and Lum Berries case, you may want to reccomend Calm Mind to help somewhat deal with the major power loss (both items also make setting up CM a bit easier too!) -You should mention Expert Belt in the same paragraph. While it usually won't improve Psystrike's power, it can let you 2HKO Physically Defensive Giratina and Lugia after Stealth Rock, and it takes good advantage of Mewtwo's coverage while letting it last longer than Life Orb. It's also usable on CM sets. -The other item to be mentioned is Mind Plate for CM variants. It's sorta the same deal as Expert Belt where you gain a bit of power without recoil, except its only for Psystrike. This is still fine for CM since after a boost, you still have enough power to 2HKO max HP Latias, Specially Defensive Giratina, and OHKO max HP Kyogre after Stealth Rock damage. -In teammates, you might want to mention Thunder Wave Kyogre, who can lure and paralyze Choice Scarf Palkia and Zekrom. -When you mention Wobbuffet as a teammate, you should mention that Encore support can really help CM Mewtwo set up. Bulky Booster -In the first paragraph, I think you should mention right away that picking the last move isn't going to be easy, because it determines what is going to beat your Mewtwo! -Mention Fire Blast somewhere (for power, and when its raining, it will actually do more to bulky Excadrill than Psystrike) -When you mention Fighting Arceus as a teammate, you should probably mention that it strikes down Dialga as well (sorta same with Landorus-T and Groudon, but if that Dialga is offensive its going to screw with them). Stalltwo -Mention that Will-O-Wisp is a REALLY great way to screw up Tyranitar and Genesect, both of whom are common Mewtwo switch-ins. -Something nice to mention about Substitute is that Substitute + Taunt in general can screw up most Pokemon that attempt to phaze Mewtwo, not just Giratina! -For Psystrike, you might want to also mention that it prevents Tentacruel from rapid spinning against you. It also helps against Taunt Thundurus. -Something to note about Darkrai is that if you run Light Screen and time your taunts right, Darkrai actually won't be able to 2HKO you with Dark Pulse >_>. Not that this Mewtwo likes Darkrai, but I wouldn't call Darkrai a 100% check to this set either! -Since you mention how Kyogre smashes through some stuff, might as well mention that Sabeleye gets ruined by the special attackers you mentioned! Choice Scarf -You should totally mention how Tricking Latias / Latios is a really nasty surprise for them! And of course, when people see Mewtwo without Life Orb damage, Giratina and Lugia like to come in, so Trick can make Mewtwo an alright lure. -Don't even mention Focus Blast, I swear that is one of the worst moves for Mewtwo ever x____x -In AC, I would make a short paragraph about some alternate ev spreads for Mewtwo. Mention that all these EV spreads will make you miss some nice speed targets though, mainly, you will miss out on fast weather based mons, RP Adamant Groudon, Scarf Skymin, and Scarf Darkrai. Also note that using these slower spreads will mean that Trick can become more risky, due to Mewtwo getting outsped by stuff it normally outspeeds. So Trick for thes spreads isn't really recommended unless your team is DESPERATE for a Giratina / Lugia lure. -The first kind is Modest spread. Modest can be nice for that extra power boost, while still outspeeding Scarf Genesect, DD Rayquaza, DD Salamence, Scarf Terrakion, and Scarf Palkia. 52 HP / 252 SpA / 204 Spe lets you outspeed up to Choice Scarf Terrakion. -If you prefer more bulk to power, use either Timid with 176 HP / 252 SpA / 80 Spe (to outspeed Scarf Terrakion), or 240 HP / 252 SpA / 16 Spe (outspeeds Scarf Palkia, DDmence, and Genesect). While the bulk doesn't really protect you from anything specficly, it does make Mewtwo fairly bulky for an average Choice Scarfer, which is nice if you don't need to outspeed Excadrill and Scarf Skymin. Other Options -Remove Expert Belt, its a bit better than other options honestly -Hmm as for Specs... keep it here for now, but I think there's a chance that this deserves a set in the future (though it'd be the last set for sure). Checks and Counters -You should probably mention that Genesect can also be an iffy switch-in because Psystrike and Aura Sphere can actually still 2HKO it! In fact, the only common switch in where Genesect won't be taking a fuck ton of damage from Psycho Killer are Calm Mind and Ice Beam. -I'd seperate the stuff about Scarfers from the whole "if Mewtwo doesn't have move x" part. Maybe put it in the same paragraph as the Genesect thing, since Scarfers are generally one of the most common ways to beat the Psycho Killer set. In the same paragraph, I'd also mention how Normal Arceus and Giratina-O can snipe Mewtwo at around 50% of its health (or 59% if you are willing to take a hit and rely on life orb recoil) with their priority moves. -While Chansey can survive some impressive stuff, that thing is really an emergency answer honestly, so I'm not sure if the mention for that should stay >_> -Since you mention the fact that Mewtwo gets worn down by Tspikes, you might also want to mention how Psycho Killer gets worn down by Sandstream as well. -Not exactly good for the first line of defense, but Thunder Wave Thundurus can sacrifice itself to ruin offensive Mewtwo, thanks to Prankster.