Direct Dynamic Diamond Overhead!! (R)

You may only cast this card during your opponent's final phase if you did not take damage during this turn, and you have a 《Prism Dragon》 on your center. [Cast Cost] [Pay 4 gauge] [Counter] Deal damage to your opponent equal to 2 plus the number of times your opponent's cards have attacked during this turn!! This card cannot be nullified, and its damage cannot be reduced. If your opponent's life would become 0 by this card, it cannot be changed by your opponent's cards. (Unrevivable)