Hundred Dragon (DLCS-EN146) - Dragons of Legend: The Complete Series Limited

Once per turn: You can have this card gain Levels equal to the number of cards you control, and if you do, it gains 100 ATK for each Level gained. These changes last until the end of this turn. If this card is sent to the GY: You can target 1 face-up monster you control that was Special Summoned from the Extra Deck; the first time that face-up monster would be destroyed by battle or card effect, it is not destroyed. You can only use this effect of "Hundred Dragon" once per turn.