Rainbow Dragon

"This card cannot be Normal Summoned or Set. This card cannot be Special Summoned except when there are at least 7 different Crystal Beast cards on your side of the field and/or in your Graveyard. You may activate either 1 or both of the following effects (the following effects cannot be activated during the turn this card was Special Summoned): Send all face-up Crystal Beast monsters on your side of the field to the Graveyard. The ATK of this card is increased by 1000 points for each card sent to the Graveyard by this effect. This effect can also be activated during your opponent's turn. Remove from play all Crystal Beast monsters in your Graveyard, to return all cards on the field to their owner's Deck(s)."