Exosister Stella (MP23-EN253) [25th Anniversary Tin: Dueling Heroes Mega Pack]

During your Main Phase: You can Special Summon 1 "Exosister" monster from your hand, then if you control "Exosister Elis", 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 Stella" once per turn.