It can be used even if you have taken no damage this turn, in order to waste the spell. So if an effect such as Worship causes some of the damage to not cause loss of life, then Reverse Damage will not give you life for the damage that did not cause loss of life. Earthquake , Hurricane , etc. Leave a lot of mana in your pool so that you burn yourself, then Reverse it. This ends up giving you only one less life than if you'd used an Alabaster Potion .
Reverse Damage is a good card if playing against red.
Just when your opponent thinks he has finished you off with one of his ten point Fireball s, you can cast this spell and turn his victory into defeat.