Exosister Elis

If you control an "Exosister" monster: You can Special Summon this card from your hand, then if you control "Exosister Stella", you gain 800 LP. If your opponent moves a card(s) out of either GY (except during the Damage Step): You can Special Summon from your Extra Deck, 1 "Exosister" Xyz Monster using this face-up card you control as material. (This is treated as an Xyz Summon.) You can only use each effect of "Exosister Elis" once per turn.