The mod in its current state makes Creepers a bit less of a threat. To compensate that, Creeperlings at higher difficulties could have a chance to spawn as Creepies instead.
Creepies have a different texture and can contaminate animals, disappearing in the process. A contaminated animal gets a special effect that slows them down, and spawns a cloud of creeper spores when they die. If the timer on the effect reaches 0, the entity suffers heavy damage and an adult creeper spawns.

at this point I can agree since creeper spores are usually communistic (or however you spell the symbiosis type where one benefits and the other isn't affected)