Agility Sweeper (Growlithe) @ Petaya Berry
Ability: Intimidate  
EVs: 4 Hp / 252 SpA / 252 Spe  
Modest Nature  
IVs: 2 Atk / 30 SpA  
- Agility  
- Fire Blast  
- Hidden Power [Grass]  
- Substitute / Crunch

Lead (Growlithe) @ Lum Berry  
Ability: Intimidate  
EVs: 80 Def / 252 SpA / 176 Spe  
Timid Nature  
IVs: 2 Atk / 30 SpA  
- Flamethrower / Fire Blast
- Hidden Power [Grass]  
- Overheat
- Toxic / Crunch
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Optional Move(s):
- N/A
Optional Item(s):
- Leftovers
Optional Ability:
- N/A
Optional EV/IV(s):
- (Modest) 184 HP / 36 Def / 252 SpA / 36 Spe
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Overview: As one of only two viable Fire-types in the metagame, Growlithe finds its place as a powerful, late-game Agility sweeper. On the contrary, Growlithe can also fit into an anti-lead slot.
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Agility Sweeper: After an Agility, Growlithe outspeeds the entire unboosted metagame, giving it an important first strike every turn. Fire Blast is Growlithe's main stab as it possesses incredible power over Flamethrower, which can be important for securing KOs on Pokémon like Elekid. Hidden Power [Grass] is crucial coverage for the many water and Rock-types that inhabit the tier, such as Rhyhorn, Chinchou, and Seaking. In the last slot, Crunch offers niche coverage designed to hit Spoink, an otherwise reliable Fire-type check thanks to its ability Thick Fat. It also is a strong neutral option for rare Dragon-types and opposing Fire-types, both of which resist the Fire- and Grass-coverage combination. Substitute is another option in this slot that allows Growlithe to activate its Petaya Berry and block status safely. 
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Lead: Lead Growlithe trades Cyndaquil's surefire matchup against Snorunt for better lead matchups overall. With 80 defense EVs and Intimidate, Growlithe is able to survive powerful Choice Band attacks from the likes of Aipom, Delibird, and Castform and fire back with its powerful STAB Overheat. Flamethrower provides 100% accurate attacks while Fire Blast hits harder, which can provide crucial when combined with Overheat. Hidden Power [Grass] allows Growlithe to effectively hit Onix, Rhyhorn, or an incoming water type. Lum berry prevents Butterfree from sleeping Growlithe immediately. Toxic is a catch-all for scouting opposing switch-ins like Chinchou and Delcatty or punishing Endure from opposing leads like Snorunt and Cyndaquil.
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Other Options: With the combination of 184 HP, 36 Defense, and Intimidate, this set focuses on giving Growlithe more bulk for sustaining itself during an agility sweep. Significantly, it allows Growlithe to survive Double-Edge from Adamant Choice Band Castform or Aipom after an Intimidate. 36 Speed EVs are required to outspeed the unboosted metagame at +2. Finally, Growlithe has the option of forgoing Agility entirely, focusing more on mid-game wallbreaking for its teammates in the back. Leftovers could be ran alongside Substitute on the Agility set, but Petaya Berry is generally more useful to boost its Special Attack to aid in a sweep. 
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Checks and Counters: Without Crunch or Toxic, Spoink can easily take attacks from Growlithe due to Thick Fat and a naturally high SpDef. Faster Water-types like Seaking or Chinchou can also switch in and threaten immediate KOs with their water STAB. SpDef Delcatty can effectively Protect + Wish stall Growlithe's Fire Blast PP and Flamethrower is too weak to pressure it.
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