If a Dragon Xyz Monster declares an attack: Attach this card on the field to it as material. You can only use each of the following effects of "Galaxy-Eyes Tachyon Primal" once per turn. If a Dragon Xyz Monster is on the field (Quick Effect): You can Special Summon this card from your hand to either field. If this card is Normal or Special Summoned: The owner of this card adds 1 "Tachyon" Spell/Trap from their Deck to their hand.