瞬间
噬物腐化对目标生物或鹏洛客造成X点伤害且你获得X点生命,X为由你操控的沼泽数量。
The value of X is calculated only once, as Consuming Corruption resolves.
If the target creature or planeswalker is an illegal target as Consuming Corruption tries to resolve, it won't resolve and none of its effects will happen. You won't gain life.