(1) If only your opponent controls a monster Special Summoned from the Extra Deck: Choose 4 “Number” Xyz Monsters with different Ranks in your Extra Deck, add the numbers in all their names together, and Special Summon 1 “Number” Xyz Monster from your Extra Deck with a number in its name equal to the result, and if you do, attach all the chosen monsters to it as material, but you cannot Special Summon monsters while you control it, except “Number” Xyz Monsters. (This is treated as an Xyz Summon.)