[Scripting Question] Mega Evolution Speed

  def pbMegaEvolve(index)
    return if !@battlers[index] || !@battlers[index].pokemon
    return if !(@battlers[index].hasMega? rescue false)
    return if (@battlers[index].isMega? rescue true)
    ownername=pbGetOwner(index).fullname
    ownername=pbGetOwner(index).name if pbBelongsToPlayer?(index)
    case (@battlers[index].pokemon.megaMessage rescue 0)
    when 1 # Rayquaza
      pbDisplay(_INTL("{1}'s fervent wish has reached {2}!",ownername,@battlers[index].pbThis))
    else
      pbDisplay(_INTL("{1}'s {2} is reacting to {3}'s {4}!",
         @battlers[index].pbThis,PBItems.getName(@battlers[index].item),
         ownername,pbGetMegaRingName(index)))
    end
    pbCommonAnimation("MegaEvolution",@battlers[index],nil)
    @battlers[index].pokemon.makeMega
    @battlers[index].form=@battlers[index].pokemon.form
    @battlers[index].pbUpdate(true)
    @scene.pbChangePokemon(@battlers[index],@battlers[index].pokemon)
    pbCommonAnimation("MegaEvolution2",@battlers[index],nil)
    meganame=(@battlers[index].pokemon.megaName rescue nil)
    if !meganame || meganame==""
      meganame=_INTL("Mega {1}",PBSpecies.getName(@battlers[index].pokemon.species))
    end
    pbDisplay(_INTL("{1} has Mega Evolved into {2}!",@battlers[index].pbThis,meganame))
    PBDebug.log("[Mega Evolution] #{@battlers[index].pbThis} became #{meganame}")
    side=(pbIsOpposing?(index)) ? 1 : 0
    owner=pbGetOwnerIndex(index)
    @megaEvolution[side][owner]=-2
  end

Generation VII

In Generation VII, a Pokémon's Speed after Mega Evolution is used to determine turn order, not its Speed before. Likewise, if a Pokémon only has an Ability such as Prankster before Mega Evolution, appropriate moves will not gain priority. If a Pokémon gains Prankster upon Mega Evolution, appropriate moves will gain priority.

Rayquaza cannot Mega Evolve if it holds a Z-Crystal.

In Pokémon: Let's Go, Pikachu! and Let's Go, Eevee!, as the Held item mechanic is not implemented, the player simply needs to have the compatible Mega Stone in their bag to access a Pokémon's Mega Evolution. The player can also manually pick which form Charizard or Mewtwo can become from the move menu.

    # Calculate priority at this time
    @usepriority=false
    priority=pbPriority(false,true)
    # Mega Evolution
    megaevolved=[]
    for i in priority
      if @choices[i.index][0]==1 && !i.effects[PBEffects::SkipTurn]
        side=(pbIsOpposing?(i.index)) ? 1 : 0
        owner=pbGetOwnerIndex(i.index)
        if @megaEvolution[side][owner]==i.index
          pbMegaEvolve(i.index)
          megaevolved.push(i.index)
        end
      end
    end
    if megaevolved.length>0
      for i in priority
        i.pbAbilitiesOnSwitchIn(true) if megaevolved.include?(i.index)
      end
    end
    # Call at Pokémon
    for i in priority
      if @choices[i.index][0]==4 && !i.effects[PBEffects::SkipTurn]
        pbCall(i.index)
      end
    end

    @usepriority=false
    priority=pbPriority(false,true)