From the uncreative department:
Toxapex @ Shed Shell
Ability: Regenerator
EVs: 248 HP / 252 Def / 8 SpD
Bold Nature
IVs: 0 Atk
- Scald
- Recover
- Haze
- Toxic Spikes/Toxic
+2 0 Atk Revenankh Shadow Claw vs. 248 HP / 252+ Def Toxapex on a critical hit: 127-150 (41.9 - 49.5%) -- 85.9% chance to 2HKO after Stealth Rock
+1 0 Atk Revenankh Shadow Claw vs. 248 HP / 252+ Def Toxapex on a critical hit: 94-112 (31 - 36.9%) -- guaranteed 3HKO after Stealth Rock
0 Atk Revenankh Shadow Claw vs. 248 HP / 252+ Def Toxapex on a critical hit: 64-76 (21.1 - 25%) -- 96.4% chance to 4HKO after Stealth Rock
You have to account for Shadow Claw's 25% crit, but a solid counter nonetheless. Even assuming Pex comes in on a second Bulk Up or a Shadow Claw after a Bulk Up, Pex Hazes it, walls it forever even with crits, sets up Toxic Spikes while fishing for burns, or straight-up Toxics it.
Toxapex @ Shed Shell
Ability: Regenerator
EVs: 248 HP / 252 Def / 8 SpD
Bold Nature
IVs: 0 Atk
- Scald
- Recover
- Haze
- Toxic Spikes/Toxic
+2 0 Atk Revenankh Shadow Claw vs. 248 HP / 252+ Def Toxapex on a critical hit: 127-150 (41.9 - 49.5%) -- 85.9% chance to 2HKO after Stealth Rock
+1 0 Atk Revenankh Shadow Claw vs. 248 HP / 252+ Def Toxapex on a critical hit: 94-112 (31 - 36.9%) -- guaranteed 3HKO after Stealth Rock
0 Atk Revenankh Shadow Claw vs. 248 HP / 252+ Def Toxapex on a critical hit: 64-76 (21.1 - 25%) -- 96.4% chance to 4HKO after Stealth Rock
You have to account for Shadow Claw's 25% crit, but a solid counter nonetheless. Even assuming Pex comes in on a second Bulk Up or a Shadow Claw after a Bulk Up, Pex Hazes it, walls it forever even with crits, sets up Toxic Spikes while fishing for burns, or straight-up Toxics it.