Cannot be Normal Summoned/Set. Must be Special Summoned (from your hand or Graveyard) by banishing 3 EARTH monsters from your hand and/or Graveyard, and cannot be Special Summoned by other ways. Rock-Type monsters you control cannot be destroyed, except by battle. If this card is sent from the field to the Graveyard: You can add up to 3 Rock-Type monsters from your Deck to your hand, whose total Levels equal 8. You can only use this effect of "Block Dragon" once per turn.