Sorcery
Destroy up to X target artifacts and/or enchantments. Create twice X 1/1 black and green Pest creature tokens with "When this token dies, you gain 1 life."
If any artifacts or enchantments were chosen as targets, and all of them are illegal targets as Pest Infestation tries to resolve, it won't resolve and none of its effects will happen. No Pests will be created.