You need to keep the poisoned creature alive to get larvae. Because the creature needs to be kept alive, that's why it's in
.
Using life to sustain more life, for instance.
But, yay, love!
I never intended for the card to be CC, so I'll give it a minor buff by having the caster of infest get the larvae, not the controller of the infested creature.
...Actually, that's a major buff, nevermind.