I wanted to try out Mega Diancie since it just came out so I decided to throw this team together. It's honestly a fairly basic team but it works just fine.
Diancie @ Diancite
Ability: Clear Body
EVs: 176 Atk / 80 SpA / 252 Spe
Naive Nature
- Moonblast
- Diamond Storm
- Hidden Power [Fire]
-...