Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
The equipped monster gains 400 ATK. If the equipped monster attacks a Defense Position monster, inflict piercing battle damage to your opponent. When this card leaves the field, banish the equipped monster.
--ビッグバン・シュート
--Big Bang Shot
local s,id=GetID()
function s.initial_effect(c)
	aux.AddEquipProcedure(c)
	--Atk down
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_EQUIP)
	e2:SetCode(EFFECT_UPDATE_ATTACK)
	e2:SetValue(400)
	c:RegisterEffect(e2)
	--Pierce
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_EQUIP)
	e3:SetCode(EFFECT_PIERCE)
	c:RegisterEffect(e3)
	--Remove
	local e5=Effect.CreateEffect(c)
	e5:SetDescription(aux.Stringid(id,0))
	e5:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_CONTINUOUS)
	e5:SetCode(EVENT_LEAVE_FIELD)
	e5:SetOperation(s.rmop)
	c:RegisterEffect(e5)
end
function s.rmop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	local tc=e:GetHandler():GetEquipTarget()
	if tc then
		Duel.Remove(tc,POS_FACEUP,REASON_EFFECT)
	end
end