If you control a "Photon" or "Galaxy" monster: Target 1 Xyz Monster you control; Special Summon from your Extra Deck, 1 "Photon" or "Galaxy" Xyz Monster that is 4 Ranks higher than that target, by using that target as material. (This is treated as an Xyz Summon. Transfer its materials to the Summoned monster.) You can only activate 1 "Eternal Galaxy" per turn.