When this card is activated: You can send 1 "Photon" or "Galaxy" card from your Deck to the GY. If "Galaxy-Eyes Photon Dragon" is Special Summoned to your field (except during the Damage Step): You can look at your opponent's Extra Deck, then you can apply 1 of these effects.
• Banish 1 monster from it.
• Special Summon 1 "Number" monster from it to your field.
You can only use this effect of "Galaxy Hundred" once per turn. You can only activate 1 "Galaxy Hundred" per turn.