I disagree with the people who have been saying that Toxapex is broken.
The HP boost is clearly a huge boon for it and it's a top tier, probably S rank Pokemon which must be taken into account when building. It's the best mixed wall and general catchall in the metagame.
But it's far from unbreakable.
First: I want to clarify something. It's impossible to boost Toxapex's bulk by more than 1.6x (1.59210526316...x :3). 140 base HP hits 484 raw HP while 50 base hits 304 raw. Still a significant boost, but not 'triple it', which is a very misleading way of looking at it.
Anyway:
There are a bunch of Pokemon capable of breaking your standard Toxapex. I'm going to go through some of them, but not all.
Code:
Swoobat @ Grassy Seed
Ability: Simple
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Calm Mind
- Roost
- Stored Power
- Heat Wave
+2 252 SpA Swoobat Stored Power (140 BP) vs. 252 HP / 4 SpD Toxapex: 474-560 (97.9 - 115.7%) -- 87.5% chance to OHKO
+2 252 SpA Swoobat Stored Power (100 BP) vs. 252 HP / 4 SpD Toxapex: 338-402 (69.8 - 83%) -- guaranteed 2HKO after Black Sludge recovery
As you can see: Swoobat is capable of beating Toxapex with or without the Grassy Seed boost (although it's easier with). This is 140 HP Toxapex, the highest you can go.
Code:
Toxtricity @ Throat Spray
Ability: Punk Rock
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
IVs: 0 Atk
- Overdrive
- Shift Gear
- Sludge Bomb
- Boomburst
252+ SpA Punk Rock Toxtricity Overdrive vs. 252 HP / 4 SpD Toxapex: 283-338 (58.4 - 69.8%) -- guaranteed 2HKO after Black Sludge recovery
252+ SpA Punk Rock Toxtricity Overdrive vs. 252 HP / 4 SpD Toxapex: 252-299 (52 - 61.7%) -- 97.3% chance to 2HKO after Black Sludge recovery
252+ SpA Toxtricity Sludge Bomb vs. 252 HP / 252+ SpD Assault Vest Tangrowth: 150-176 (37.1 - 43.5%) -- guaranteed 3HKO
First calc is Lunala SpA (boosted, but not insane) second two are its normal SpA. Pex has 140 HP Growth has 95 SpD (both from Eternatus). Pex just dies, Growth gets Regen outdone and Poisoned. It's capable of breaking the Pex/Growth core all by itself, with or without Throat Spray being used, although it can't 1v1 Tangrowth well and has to hit it coming in.
Code:
Necrozma-Dusk-Mane @ Leftovers
Ability: Prism Armor
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Photon Geyser
- Dragon Dance
- Earthquake
- Morning Sun
252+ Atk Necrozma-Dusk-Mane Photon Geyser vs. 252 HP / 252+ Def Toxapex: 222-264 (45.8 - 54.5%) -- 5.9% chance to 2HKO after Black Sludge recovery
252 Atk Life Orb Necrozma-Dusk-Mane Photon Geyser vs. 252 HP / 252+ Def Toxapex: 265-312 (54.7 - 64.4%) -- guaranteed 2HKO after Black Sludge recovery
There are a bunch of possible NDM sets. I'm not going into all of them here. If they have Photon Geyser they break Pex.
Code:
Indeedee (M) @ Choice Specs
Ability: Psychic Surge
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Expanding Force
- Hyper Voice
- Mystical Fire
- Trick
252 SpA Indeedee Expanding Force (120 BP) vs. 252 HP / 4 SpD Toxapex in Psychic Terrain: 324-384 (66.9 - 79.3%) -- guaranteed 2HKO after Black Sludge recovery
Standard Indeedee breaks Pex. Most Indeedee boost either SpA or Speed, so don't be surprised to take more.
Code:
Rhyperior @ Life Orb / Choice Band / Weakness Policy
Ability: Solid Rock
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature / Adamant
- Earthquake
- Rock Slide
- Megahorn
- Swords Dance / Stealth Rock / Rock Polish
252 Atk Life Orb Rhyperior Earthquake vs. 252 HP / 252+ Def Toxapex: 242-283 (50 - 58.4%) -- 67.2% chance to 2HKO after Black Sludge recovery
252 Atk Life Orb Rhyperior Megahorn vs. 252 HP / 252+ Def Tangrowth: 221-263 (54.7 - 65%) -- guaranteed 2HKO
This guy needs Speed. But breaks the mentioned core nicely, even without SD.
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These options all require minimal support and are fairly flexible to fit on teams, although their viability is somewhat mixed. I didn't want to have options that only fit on specific archetype because then the easy call is 'but what if I'm not running x team'. But since this is Godly Gift let me point out: almost every god gives access to absurd wallbreakers (if you're using Shuckle as a god IDK what to tell you

). I've found you can use that to crack even the toughest walls with smart play and smart builds.
Also use Swoobat it's insane swiggity-