Grumpig

Own Tempo
Cannot be confused.
Thick Fat
Halves Ice and Fire damage.
Type Tier
Psychic UU
Statistics
Min- Min Max Max+
HP
80
- 301 364 -
Atk
45
113 126 189 207
Def
65
149 166 229 251
SpA
90
194 216 279 306
SpD
110
230 256 319 350
Spe
80
176 196 259 284
Name Item Ability Nature

Calm Mind Sweeper

Leftovers Thick Fat Timid
Moveset EVs
~ Calm Mind
~ Substitute
~ Psychic
~ Hidden Power Bug / Hidden Power Fighting
252 HP / 20 SpD / 236 Spe

Grumpig was one of the very first Advance Pokémon to obtain Substitute and has always kept it since. The idea of Substitute is to keep Grumpig away from nasty status like Toxic and maintain a guard against faster physical sweepers, so you can Calm Mind safely. Hidden Power Bug offers the best coverage alongside Psychic, as it hurts Psychics and Darks, two of the three types that resist Grumpig's STAB move. Only Steel types wall Psychic/Bug, but Aggron and Mawile won't enjoy boosted STAB Psychics, and you can simply set up against the offensively inept Probopass and Bastiodon (beware of Taunt). HP Fighting easily takes out Steels, and also hits Darks. However, if you are up against another Psychic with a super-effective attack (or Hypno with Seismic Toss), you may be in trouble.

If you can't obtain HP Bug for WiFi battles, Shadow Ball will cover Psychics (but leave you helpless against Darks, other than Sableye). Energy Ball hits most Psychics and Darks neutral and even scores super effective hits on a few, such as Lunatone, Solrock, Sharpedo and Crawdaunt. Beware of Cacturne, Shiftry, Skuntank and Honchkrow if you carry Energy Ball. If you want perfect coverage, Shadow Ball and Hidden Power Fighting work, but this forces you drop STAB Psychic, which is not recommended in most cases.

The EV spread might not suggest as such, but this Grumpig is quite a fearsome sweeper. With Thick Fat, enough Speed for some major threats in OU and UU alike, and extremely sturdy Substitutes, this is one Pokémon to watch out for.

Name Item Ability Nature

Choice

Choice Specs / Choice Scarf Thick Fat Modest
Moveset EVs
~ Trick
~ Psychic
~ Shadow Ball
~ Hidden Power Fighting / Focus Blast
64 HP / 252 SpA / 192 Spe

Tricking is very evil. If you switch in Grumpig on a random attack and they see you don't have Leftovers they might see it coming, but otherwise you can expect to fool something like Solrock into accepting the Choice Specs. If you obtain a Choice Band from something in return, try Tricking that on something else. It brings along some difficult mindgames sometimes. Of course, the great thing about Tricking Grumpig is that you don't have to use Trick right away: feel free to abuse either Choice item as long as you can to either fire boosted special hits or hit something that doesn't expect you to be faster (hello there, Fearow). Calm Mind can be used on this set to try and set up after Tricking.

Name Item Ability Nature

Rest/Sleep Talk

Leftovers Thick Fat Calm
Moveset EVs
~ Rest
~ Sleep Talk
~ Psychic
~ Toxic / Hidden Power Bug / Calm Mind
252 HP / 160 Def / 96 SpD

This set truly takes advantage of that great 110 Special Defense Grumpig has. This Grumpig can be freely switched into almost any Special threat in UU and shrug it off as if it never happened. Toxic helps in stallwars against things that do not Rest like you do, and Calm Mind is usually for those that do. The Defense EVs are there to keep you alive versus some physical attackers during Rests, but don't let Grumpig face off Choice Banders or something heavy powered like that.

Other Options

Charge Beam can be used to boost your Special Attack without using Calm Mind and gives you a little more versatility. While Psychic/Electric isn't the best coverage in the game, at least it works on these Water/Psychic types as well as Sharpedo, Honchkrow and Crawdaunt. Psych Up can nick other people's Calm Minds. Focus Blast is inaccurate, but deals with nuisances in OU that Grumpig usually can't help (Blissey, Tyranitar, some Steels). Focus Punch does the same, but is harder to pull off and screws up your EV spread or ends up getting cushioned to easily. If you're thinking of using Grumpig in OU, you might want to use Grass Knot over Energy Ball, as it does more damage on heavy things like Milotic, Rhyperior, and Tyranitar. Reflect and Light Screen are nice and offer support.

Counter is awesome on Grumpig, as people should target his 65 Defense all the time. Especially if you're setting up Calm Mind. Please consider.

EVs

If you're going to sweep, you'll need some Speed. 280 Speed beats Pikachu, Zangoose and a few others to the punch. Choice Scarf sets can settle for less—270 in OU (beats standard Heracross), while 242 is plenty in UU (beats Persian). With Calm Mind there's not much need to pump Special Attack, so HP and Special Defense are welcome to take hits better. Defensive or Counter sets don't need much if any Speed and can focus entirely on staying alive.

Opinion

A premiere force in UU, rivaled only by Hypno for the best special wall there. Hypno is the more versatile wall now that he gained Switcheroo while maintaining Baton Pass. Nonetheless, Grumpig does better at taking Fire and Ice hits thanks to Thick Fat, and is more dangerous as a sweeper.

In OU, Grumpig is an underdog that should try to distinguish himself from the likes of Blissey, Azelf, and Alakazam.

Counters

In UU, Seismic Toss Hypno can test his set and work from there—beware of Trick, HP Bug and Shadow Ball. If Grumpig starts to snooze, send in some heavy physical hitter to knock him out. Pursuit can work wonders if you have it. Dark types like Honchkrow and Skuntank can put a great hurting on him, as he is unlikely to carry any attack that is super-effective on either of them.

In OU, Blissey, Snorlax, Spiritomb, and pretty much every other special wall that can do a decent amount of damage, will easily defeat Grumpig.