OU 4.. Dual tech + sniping barbaracle

Milotic (F) @ Leftovers
Ability: Marvel Scale
EVs: 56 HP / 180 Def / 132 SpA / 140 SpD
Calm Nature
IVs: 0 Atk
- Haze
- Scald
- Recover
- Hidden Power [Fire]

Ambipom (F) @ Silk Scarf
Ability: Technician
Shiny: Yes
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Aerial Ace
- Fake Out
- Knock Off
- Return

Gliscor (M) @ Toxic Orb
Ability: Poison Heal
EVs: 84 HP / 20 Atk / 236 Def / 168 SpD
Impish Nature
- Earthquake
- Rock Slide
- Roost
- Toxic

Scizor-Mega (M) @ Scizorite
Ability: Technician
EVs: 112 HP / 244 Atk / 100 Def / 52 Spe
Adamant Nature
- Bug Bite
- Bullet Punch
- Swords Dance
- Roost

Serperior (F) @ Choice Specs
Ability: Contrary
EVs: 8 Atk / 248 SpA / 252 Spe
Naive Nature
- Leaf Storm
- Dragon Pulse
- Hidden Power [Rock]
- Aqua Tail

Barbaracle (M) @ Scope Lens
Ability: Sniper
EVs: 64 HP / 168 Atk / 24 Def / 252 Spe
- Razor Shell
- Stealth Rock
- Stone Edge
- Earthquake

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Substitutions can be protect over roost on gliscor, a bulkier barbaracle has shown to work effectively as well.

Life orb latios can be used to replace serperior (gives you more bulk and hazard control)