This should make it a lot easier to add new Pokémon:
ItemHandlers::UseOnPokemon.add(:DEVOLUTIONSTONE,proc{|item,pokemon,scene|
evos = {
# :SPECIES => :BABY,
:NINETALES => :VULPIX,
}
hash = {}
evos.each { |e| hash[getConst(PBSpecies,e[0])] = e[1] }
if hash[pokemon.species]...