As an additional cost to cast this spell, sacrifice a creature.
Create X 1/1 black and green Pest creature tokens with "When this creature dies, you gain 1 life," where X is the sacrificed creature's power.
Copies of Tend the Pests will use the power of the creature sacrificed for the original spell to determine the number of Pests each copy creates. Because the copies aren’t cast, you won’t sacrifice additional creatures for them.