Many spells specify a condition (animal, living creature, undead, etc.) that their targets must fulfill. What happens if such a spell is cast on a target that meets the condition(s), but changes in such a way that it no longer does at some point while the spell is active?
The specific case I'm wondering about is something one of my players wants to do - his plan is to buff an animal with animal growth, charm it, speak with it to convey his wishes and hopefully sway it with his impressive Charisma score, then finally polymorph it into a human or other non-animal, still buffed with animal growth.
My first instinct is to say that animal growth is ended when the target changes shape, but I'd like to know if there's another way of looking at this, or if there is any precedent for such a combination.