His reactions to my moves:
Sleep Powdered a lot with Roselia
Prioritised rocks, sent it in on my Defog Florges a ton and got them up easily
Dialga was his switch in to my Lugia and Ash-Gren, so Sp Def? (Definitely Max HP)
Mawile has very little Attack, more bulky
Rotom-Wash probably physically defensive for Charizard
Near Max Attack Jolly Zygarde, VERY bulky (sp def)

Rotom-Wash @ Leftovers
Ability: Levitate
Level: 50
IVs: 0 Atk
- Hydro Pump
- Thunder Wave
- Volt Switch
- Foul Play

Dialga @ Leftovers
Ability: Pressure
Level: 50
EVs: 252 HP
IVs: 0 Atk
- Aura Sphere
- Toxic
- Roar

Mawile-Mega @ Mawilite
Ability: Huge Power
Level: 50
EVs: 124 Atk
- Play Rough
- Brick Break
- Knock Off
- Stealth Rock

Gengar @ Choice Scarf
Ability: Cursed Body
Level: 50
IVs: 0 Atk

Roselia @ Eviolite
Ability: Natural Cure
Level: 50
IVs: 0 Atk
- Leech Seed
- Sleep Powder

Zygarde-Complete @ Yache Berry
Ability: Power Construct
Level: 50
EVs: 248 Atk
- Thousand Arrows
- Dragon Dance