Lord Gaia the Fierce Knight - MVP1-EN050 Ultra Rare 1st Edition

If your opponent controls a monster and you control no monsters, you can Special Summon this card (from your hand). Once per turn, if a monster(s) with ATK higher than this card is Special Summoned to your opponent's field (except during the Damage Step): You can make this card gain 700 ATK until the end of this turn.