Once per turn, if you Normal or Special Summon a "Gunkan" monster(s) (even during the Damage Step): You can place 1 "Gunkan" card from your Deck on the top of your Deck. Once per turn, if your "Gunkan" monster(s) Special Summoned from the Extra Deck is sent to the GY by an opponent’s card: Your opponent must pay LP equal to its DEF, then you can Special Summon 1 "Gunkan Suship Shari" from your hand, and if you do, immediately after this effect resolves, Xyz Summon 1 "Gunkan" Xyz Monster using only that monster as material.
