Here's an EZPZ check to -ate Extreme Speed. You're welcome.
Steelix @ Blue Orb
Ability: Sturdy
EVs: 248 HP / 252 Atk / 8 Def
Brave Nature
IVs: 0 Spe
- Gyro Ball
- Earthquake/Aqua Tail/Stone Edge
- Ice Fang
- filler (Thunder Fang/Earthquake)
Steelix's unparalleled combination of typing and sheer raw Defense lets it shrug off any type of Extreme Speed as if it were just a breeze. It can then counter Altarianite Extreme Speed users, all of whom carrying significantly large Speed stats, with a Super Effective STAB Gyro Ball . . . unless the user is Fire, Water, or Electric-type, of course.
Since the Fire-type Extreme Speeders are the most popular right now (being notably difficult to counter, for reasons including but not limited to an immunity to Burn), they gain an extra special focus with this set, with Blue Orb giving Steelix a much-welcome immunity to Fire-type attacks, and an entire move slot (or two) dedicated to exploiting Fire's weaknesses. STAB Earthquake does the most raw damage, being a guaranteed OHKO against any Fire/Fairy-type Extreme Speed user, but it has a noteworthy drawback of not touching Fire/Flying-types at all (which is why I personally use Pinsirite Entei--it's extremely easy to get a free turn off of people who think you are running the Altarianite set). Conversely, Stone Edge hits Fire/Flying-types the hardest of any of these moves, but its infamously shaky Accuracy will make you question its value against Pokémon without a double-weakness to Rock. Aqua Tail is like a happy middle ground between Earthquake and Stone Edge, receiving virtual STAB from Blue Orb and hitting all Fire-type Extreme Speeders with relative consistency.
Ice Fang has one specific purpose: hitting Zygarde, the most popular non-Fire type Extreme Speed user, when it isn't using Altarianite. STAB Earthquakes hurt Steelix a lot, though, so be ready with a backup plan in case it gets the 2HKO. Under no circumstances should you allow it to set up Dragon Dance, however.
The last slot I recommend filling with your coverage move of choice. If you put Stone Edge in the second slot, Earthquake can compliment it here; conversely, Thunder Fang can compliment Ice Fang by hitting physical Water and Flying types that might want to come out and play in the rain.
Just as this set checks Extreme Speed attackers (especially the Fire-type ones, whose best options are to hit it with something weaksauce like Bulldoze), this set can in and of itself be checked. It still takes x2 damage from Ground and Fighting, and an effective x3 damage from Water. Furthermore, its special bulk leaves a lot to be desired. Its worst nightmares are STAB Scald users and Pidgeotite Keldeo. Pair this set with a Pokemon that can soak special hits and resistances/immunity to its weaknesses. For an example:
Giratina @ Leftovers
Ability: Pressure
EVs: 248 HP / 252 Def / 8 SpA
Bold Nature
IVs: 0 Atk
- Will-O-Wisp
- Ancient Power
- Calm Mind
- Pain Split
Poor(?) Giratina seems to have difficulty catching a break in this format, and I know what you're thinking: "I thought you said I needed a special wall! What gives with the physical defense? Ancient Power?!?" Patience, grasshopper. Clear your mind, and you will see that after one turn of boosting, its massive natural special bulk already outpaces anything its EVs and Nature could possibly give. This is handy if you switched it in against a Pidgeotite Hydro Pump (or, better yet, Focus Blast), as this gives Giratina ample time to set up. Should a (non-Fire type) physical attacker switch in, it will appreciate its added physical toughness for soaking a hit long enough to apply Will-O-Wisp. Keep boosting with Calm Mind, and do not be scared of sharing your pain with others should it threaten to become too much to bear. More Calm Mind, and if your opponent has not had the wisdom of simply asking Giratina nicely to leave, you are ready to strike.
Ancient Power . . . the Fire-type Pokemon immune to Will-O-Wisp were considered when selecting this move. Yes, Giratina has stronger attacks it can use against some of them, and even gets STAB on a couple of them, but Dragon, Ground, and Ghost-type attacks all have one problem in common: they all do 0 damage to Pokémon with certain types or even (in the case of Ground) Abilities. Rock-type moves have no such problem, and Fire-types need to be hit hard by whatever Giratina is attacking with, as they cannot be worn down by Will-O-Wisp, so this left Ancient Power as the best remaining move in Giratina's arsenal. If Power Points are a concern, you may opt for Dark Pulse instead, as even against most Fire-types, it will get you twice as far as Ancient Power would in the long run. That being said, with sufficient Calm Mind usage, you shouldn't have that much trouble obliterating your opponent with anything they don't have an immunity to.
Physical Fire-type attackers with proper coverage (e.g., Pixilate Extreme Speed users) give this set too much trouble too quickly, so this set, as alluded to earlier, pairs nicely with the above Steelix set. Ice, Ground, Ghost, and Dark attacks threaten either set with neutral or greater damage, however, so be sure to include answers to threatening examples of those elsewhere on your team.