Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
When your opponent Special Summons a monster (except during the Damage Step): You can discard 1 card; Special Summon this card from your hand. Your opponent cannot banish cards.
--カオスハンター
--Chaos Hunter
local s,id=GetID()
function s.initial_effect(c)
	--Special summon
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_O)
	e1:SetRange(LOCATION_HAND)
	e1:SetCode(EVENT_SPSUMMON_SUCCESS)
	e1:SetCondition(s.spcon)
	e1:SetCost(s.spcost)
	e1:SetTarget(s.sptg)
	e1:SetOperation(s.spop)
	c:RegisterEffect(e1)
	--Cannot remove
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_FIELD)
	e2:SetCode(EFFECT_CANNOT_REMOVE)
	e2:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
	e2:SetRange(LOCATION_MZONE)
	e2:SetTargetRange(0,1)
	c:RegisterEffect(e2)
	--Imperial Iron Wall check
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_FIELD)
	e3:SetCode(30459350)
	e3:SetRange(LOCATION_MZONE)
	e3:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
	e3:SetTargetRange(0,1)
	c:RegisterEffect(e3)
end
function s.spfilter(c,sp)
	return c:GetSummonPlayer()==sp
end
function s.spcon(e,tp,eg,ep,ev,re,r,rp)
	return eg:IsExists(s.spfilter,1,nil,1-tp)
end
function s.spcost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(Card.IsDiscardable,tp,LOCATION_HAND,0,1,e:GetHandler()) end
	Duel.DiscardHand(tp,Card.IsDiscardable,1,1,REASON_COST|REASON_DISCARD,e:GetHandler())
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and e:GetHandler():IsCanBeSpecialSummoned(e,0,tp,false,false) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,e:GetHandler(),1,0,0)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if not c:IsRelateToEffect(e) then return end
	Duel.SpecialSummon(c,0,tp,tp,false,false,POS_FACEUP)
end