There is a dead pixie that the PCs have been carrying around for a couple of days, and based on an unsubstantiated story they were told* they want to feed it to a PC's giant goat companion. Because it's been unrefrigerated for a couple days the Paladin (Oath of the Crown) prepared Purify Food and Drink so it will be safe to eat:
All nonmagical food and drink within a 5-foot-radius sphere centered on a point of your choice within range is purified and rendered free of poison and disease.
The question is whether or not a pixie corpse meets the required criteria for this spell:
- is it food?
- is it nonmagical?
Since virtually everything organic is food for something else, the definition of food needs some limitation.
I've heard an argument that says since the source of this spell is divine, whatever your god would deem as food is acceptable. However, since our Paladin has no god and her loyalty lies with a dragonborn prince who is game to eat anything, this feels like a loophole. Additionally, whose perspective do you take into account? In this case, the intended consumer is an herbivore (the giant goat), but the Paladin who would be casting it is an omnivore. Does the definition of food matter to the one casting the spell, or the one for whom the food is intended?
For the second criterion, are fey innately magical? If so, do they remain magical after death?
* Someone told them about an ape that devoured pixies and over time mutated into a murderous King Kong–sized monster.
Best Answer
The PCs are testing the rumor—so make a choice!
Your campaign is a custom one, so while purify food and drink maybe should apply only to food and drink that's consumable by a creature of the race casting the spell or by the god that grants the spell or something, that doesn't mean the campaign's pixies aren't actually food for everybody.
In other words, the PCs have heard rumors of a creature that gains power via snacking on pixies, so when the PCs cast purify food and drink on a pixie corpse and they or their goat friend is about to dig in, you've to decide if those rumors of greatness through faerie feasting are true. (Fun Fact: PCs—and players!—will likely be disappointed if such rumors are untrue.)
If the rumors aren't true, the spell simply fails. No harm, no foul, no pixie picnic, no übergoat. All done.
If the rumors are true, then you've to decide how true. Can anyone partake of this pixie power-up? Need the pixie be alive? (Ew.) Some degree of fresh? (A day sounds good.) Must the entire pixie be consumed? ("Pixie wings taste like fruit roll-ups!") Is that healthy? (Likely not.) Must pixie be prepared a certain way? ("It must be served... on a stick!") Do a certain number need to be consumed to gain ultimate pixie power? And so on. Then the spell works, but, maybe, after consuming the pixie, the PCs are left wondering why their goat has a bellyache instead of awesome pixie powers.
This is your campaign, and—to challenge the frame a bit—this is less about how the spell purify food and drink works and more about the effects of pixie-eating in your campaign. That is, determine event's outcome and steps required to reach it first, and the question about the spell likely answers itself.