cr:1.9.1b

If an event comprises an instruction to do nothing, the event does not occur. It cannot be modified by replacement effects and does not trigger effects.

Example: Blazing Aether has the text “Deal X arcane damage to target hero, where X is the amount of arcane damage you have dealt to that hero this turn.” If the player has dealt 0 arcane damage this turn, the resolution of Blazing Aether produces an event that deals 0 arcane damage. Because dealing 0 arcane damage is an instruction to do nothing, it simply does not occur. It cannot be modified to deal more arcane damage by replacement effects, and it does not trigger effects for dealing arcane damage.