Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Cannot be Special Summoned. This card can attack twice during each Battle Phase. If this card attacks a Defense Position monster, inflict piercing Battle Damage to your opponent.
--ダークネス・デストロイヤー
--Darkness Destroyer
local s,id=GetID()
function s.initial_effect(c)
	--cannot special summon
	local e1=Effect.CreateEffect(c)
	e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_UNCOPYABLE)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_SPSUMMON_CONDITION)
	c:RegisterEffect(e1)
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetCode(EFFECT_PIERCE)
	c:RegisterEffect(e2)
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_SINGLE)
	e3:SetCode(EFFECT_EXTRA_ATTACK)
	e3:SetValue(1)
	c:RegisterEffect(e3)
end