You apply a magical film made of gold to the target, which magically amplifies any damage they are about to take. You may activate this spell when the enemy recieves damage, but before it is applied (even if you know how much damage will be done beforehand).

You reach out and touch a creature. When you do, the next application of damage applied to the creature ignores Resistances. If there is no resistance for the damage type, they take double damage instead, as if they had a Damage Vulnerability to it. The spell ends once the creature takes the additional damage, or at the end of your next turn..

As an example, an attack from a Flametongue Sword would normally deal 1d8 + 2d6 damage. Against a Gilded enemy with with Fire resistance, the enemy would take 2d8 + 2d6 damage.