Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
You can Tribute 3 Level 3 or lower WATER monsters; Special Summon this card from your hand or Graveyard. When you do: Return all Spell and Trap Cards on the field to the hand, and if you do, if 3 or more cards are returned to the hand by this effect, all monsters your opponent currently controls lose 300 ATK for each.
--海皇龍 ポセイドラ
--Poseidra, the Atlantean Dragon
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_IGNITION)
	e1:SetRange(LOCATION_HAND|LOCATION_GRAVE)
	e1:SetCost(s.spcost)
	e1:SetTarget(s.sptg)
	e1:SetOperation(s.spop)
	c:RegisterEffect(e1)
	--return
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetCategory(CATEGORY_TOHAND)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e2:SetCode(EVENT_SPSUMMON_SUCCESS)
	e2:SetCondition(s.thcon)
	e2:SetTarget(s.thtg)
	e2:SetOperation(s.thop)
	c:RegisterEffect(e2)
end
function s.cfilter(c)
	return c:IsLevelBelow(3) and c:IsAttribute(ATTRIBUTE_WATER)
end
function s.spcost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.CheckReleaseGroupCost(tp,s.cfilter,3,false,aux.ReleaseCheckMMZ,nil) end
	local g=Duel.SelectReleaseGroupCost(tp,s.cfilter,3,3,false,aux.ReleaseCheckMMZ,nil)
	Duel.Release(g,REASON_COST)
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.GetLocationCount(tp,LOCATION_MZONE)>-3
		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,1,tp,tp,false,false,POS_FACEUP)
end
function s.thcon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():GetSummonType()==SUMMON_TYPE_SPECIAL+1
end
function s.thfilter(c)
	return c:IsSpellTrap() and c:IsAbleToHand()
end
function s.thtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return true end
	local g=Duel.GetMatchingGroup(s.thfilter,tp,LOCATION_ONFIELD,LOCATION_ONFIELD,nil)
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,g,#g,0,0)
end
function s.thop(e,tp,eg,ep,ev,re,r,rp)
	local g=Duel.GetMatchingGroup(s.thfilter,tp,LOCATION_ONFIELD,LOCATION_ONFIELD,nil)
	Duel.SendtoHand(g,nil,REASON_EFFECT)
	local ct=g:FilterCount(Card.IsLocation,nil,LOCATION_HAND)
	if ct>=3 then
		local mg=Duel.GetMatchingGroup(Card.IsFaceup,tp,0,LOCATION_MZONE,nil)
		local tc=mg:GetFirst()
		for tc in aux.Next(mg) do
			local e1=Effect.CreateEffect(e:GetHandler())
			e1:SetType(EFFECT_TYPE_SINGLE)
			e1:SetCode(EFFECT_UPDATE_ATTACK)
			e1:SetValue(-ct*300)
			e1:SetReset(RESET_EVENT|RESETS_STANDARD)
			tc:RegisterEffect(e1)
		end
	end
end