What happens if you stop meeting the requirements for a spell?

Question

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.

Answer 1

While, as Matthew Najmon points out, this works in this case because you misunderstood the effects of the polymorph spell, in the general case it also works. The requirements for a spell to take effect only matter when the spell comes into effect. This is why, for example, Minor Creation doesn't immediately fail once the created object leaves the 0 ft. range requirement or becomes attended and Animate Objects works as described. Even if your player uses Awaken instead of Polymorph the buff will still last its duration (unless interfered with in other ways), though the spell could not be re-cast on the creature since it would no longer be a valid target.

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Addendum for those particularly interested in the nature of the RAW on this topic:

The RAW do not explicitly state that spells do end if a target/subject stops being a valid target/subject, so the effects don't end under that condition if the only rules are the RAW (because, by default, things don't happen), though the GM can certainly rule otherwise without violating the RAW. The problem with doing so is that many of the spells that do change a creatures type (e.g. those cited above) can target only a certain type of creature other than the end type, clearly indicating the Rules As Intended are the interpretation I advocate here.

This isn't particularly relevant to playing the game or the question, however, as any contrarian parsimonious ruling will render most spells functionally unusable and raise questions as to the nature of simultaneity.

Answer 2

He could even cast Animal Growth last, and it would still work. Polymorph does not change the target's creature type. Note that it also doesn't buff the creature's intelligence, so while the creature would gain such useful things as opposable thumbs, it would still be operating on animal-level intelligence.

Rules citations: the Polymorph subschool, and the Polymorph spell itself. They could have been a bit more clear and direct on this particular point, but reading carefully through all of that does eventually lead to the conclusion that nothing in the spell or the rules that go with it allow for the creature type to change, and the Polymorph subschool rules do call out that the spells only do what it says, so if it doesn't say the type changes, then it doesn't.