While you control a monster, except Poseidra, the Storming Atlantean , your opponent s monsters cannot target this card for attacks. You can only use each of the following effects of Poseidra, the Storming Atlantean once per turn. You can send 1 other WATER monster from your hand or face-up field to the GY; Special Summon this card from your hand. If this card is Normal or Special Summoned: You can send 1 Atlantean or Mermail monster from your Deck to the GY, then target 1 card your opponent controls; return it to the hand.