Water. Machine/Xyz/Effect. 2 Level 8 monstersDuring either player's turn: You can banish 1 random face-down monster from your opponent's Extra Deck, face-up, and if you do, this card's ATK becomes equal to the banished monster's. During either player's turn: You can detach 1 Xyz Material from this card, then target 1 of your opponent's banished Fusion, Synchro, or Xyz Monsters; return it to the Extra Deck, and if you do, destroy 1 monster your opponent controls with the same monster card type (Fusion, Synchro, or Xyz). You can only use each effect of "Aegaion the Sea Castrum" once per turn.