Mega Evolution animation

[Mewtwo98]

Hello guys,
I have an idea with mega evolution anim..i want to show differents anim for each types or species and i was trying to do it in script "PokeBattle_Battle" at line 1568 when it says pbCommon...etc.
I've tryied to put return.... if.... But it doesn't work.
Any Help?? Thanks in advance.

so...

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)
pbDisplay(_INTL("{1} receive power from {3}'s Soul!",
@battlers[index].pbThis,
PBItems.getName(@battlers[index].item(true)),
ownername))
pbShowEvolution(pkmn,item) <------ HERE
@battlers[index].pokemon.makeMega
@battlers[index].form=@battlers[index].pokemon.form
@battlers[index].pbUpdate(true)
@scene.pbChangePokemon(@battlers[index],@battlers[index].pokemon)
meganame=@battlers[index].pokemon.megaName
if !meganame || meganame==""
meganame=_INTL("Mega {1}",PBSpecies.getName(@battlers[index].pokemon.species))
end
pbDisplay(_INTL("{1} has Megaevolved into {2}!",@battlers[index].pbThis,meganame))
side=(pbIsOpposing?(index)) ? 1 : 0
owner=pbGetOwnerIndex(index)
@megaEvolution[side]=-2
end

And in a separate script..

def pbShowEvolution(pkmn,item)
if isCost?(pkmn.species, PBSpecies,:CHARIZARD) || isConst?(item, PBItems,:FIRESOUL)
return pbCommonAnimation("Fireevolution",@battlers[index],nil)
end
if isCost?(pkmn.species, PBSpecies,:VENUSAUR) || isConst?(item, PBItems,:NATURESOUL)
return pbCommonAnimation("Natureevolution",@battlers[index],nil)
end
return nil
end