Create a Mega/Form that can fix a pokemon:

Mega-Meganium
Thick Fat or Regenerator

HP: =
ATK: =
Def: +40
Spatk: +25
SpDef: +40
Speed: =

Meganium just needs a decent ability, I made the Calc and it can endure an Ice beam by P-Kyogre with the defense buffs without the Thick Fat