Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If the only monster you control is "Worm Xex", you can Special Summon this card from your Graveyard in face-down Defense Position. If you do, remove it from play when it is removed from the field. When this card is flipped face-up, select 1 face-up monster your opponent controls, and return it to its owner's hand.
--ワーム・ヤガン
--Worm Yagan
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_GRAVE)
	e1:SetCondition(s.spcon)
	e1:SetTarget(s.sptg)
	e1:SetOperation(s.spop)
	c:RegisterEffect(e1)
	--flip
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetCategory(CATEGORY_TOHAND)
	e2:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e2:SetCode(EVENT_FLIP)
	e2:SetTarget(s.thtg)
	e2:SetOperation(s.thop)
	c:RegisterEffect(e2)
end
s.listed_names={11722335}
function s.cfilter(c)
	return c:IsFaceup() and c:IsCode(11722335)
end
function s.spcon(e,tp,eg,ep,ev,re,r,rp,chk)
	return Duel.GetFieldGroupCount(tp,LOCATION_MZONE,0)==1
		and Duel.IsExistingMatchingCard(s.cfilter,tp,LOCATION_MZONE,0,1,nil)
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,POS_FACEDOWN_DEFENSE) 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 Duel.GetLocationCount(tp,LOCATION_MZONE)<=0 or not s.spcon(e,tp,eg,ep,ev,re,r,rp,0) then return end
	if c:IsRelateToEffect(e) and Duel.SpecialSummon(c,0,tp,tp,false,false,POS_FACEDOWN_DEFENSE)>0 then
		Duel.ConfirmCards(1-tp,c)
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_LEAVE_FIELD_REDIRECT)
		e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE)
		e1:SetReset(RESET_EVENT|RESETS_REDIRECT)
		e1:SetValue(LOCATION_REMOVED)
		c:RegisterEffect(e1,true)
	end
end
function s.filter(c)
	return c:IsFaceup() and c:IsAbleToHand()
end
function s.thtg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsControler(1-tp) and chkc:IsLocation(LOCATION_MZONE) and s.filter(chkc) end
	if chk==0 then return true end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_RTOHAND)
	local g=Duel.SelectTarget(tp,s.filter,tp,0,LOCATION_MZONE,1,1,nil)
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,g,#g,0,0)
end
function s.thop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc and tc:IsFaceup() and tc:IsRelateToEffect(e) then
		Duel.SendtoHand(tc,nil,REASON_EFFECT)
	end
end