Cactus Game Design Message Boards

Instant abilities are special abilities that complete when the card is played or otherwise activated, and do not have ongoing effects. Any instant ability whose effects resolved in a previously completed phase, even during the same turn, cannot be interrupted or negated. Effects that complete in a phase can only be undone in the phase they completed.
An instant ability chooses its targets at the time it is activated. If an instant ability is prevented from activating, then it cannot choose a target. Even if the ability that stopped it from activating is later negated, the instant ability still cannot activate because no target was initially chosen and the target cannot change.