Sacred Tree Dragon, Rainbow Cycle Dragon

(Usable when both fighters' vanguards are grade 3 or greater, and the number of face up G guardians in your G zone is three or less)-Opponent Turn's Guard Step-[Choose a card with "[Heal] Heal" from your hand, and discard it] Call this card to your from face down. :[Choose two normal units with the same card name from your drop zone, and put them on the bottom of your deck in any order] When this unit is put face up into your G zone, you may pay the cost. If you do, turn this card face down. (Does not activate when this card in your G zone is turned face up for cost)