Giant Kra-Corn

“When an opponent's monster declares an attack: You can Special Summon this card from your hand in Defense Position, and if you do, change the attack target to this card, and perform damage calculation. You can target 1 Plant monster you control, except "Giant Kra-Corn"; the ATK of that monster and this card become the combined original ATK of both monsters. You can only use each effect of "Giant Kra-Corn" once per turn.”