Does Gentle Repose work on a Circle of Spore Druid's Fungal Infestation Ability?

Question

The Circle of Spores Druid feature Fungal Infestation states:

If a beast or humanoid that is Small or Medium dies within 10 feet of you, you can use your reaction to animate it, causing it to stand up immediately with 1 hit point. The creature uses the zombie statistics. It remains animate for 1 hour, after which time it collapses and dies.

Circle of Spore druids also gain access to the Gentle Repose spell, which states:

You touch a corpse or other remains. For the duration, the target is protected from decay and can’t become undead. The spell also effectively extends the time limit on raising the target from the dead, since days spent under the influence of this spell don’t count against the time limit of spells such as raise dead.

There seem to be some good arguments that they cannot work together:

• First, Gentle Repose states the target cannot become undead, which would seem to preclude Gentle Repose working on a fungally infested creature that appears to be in some sense raised from the dead.
• Second, gentle repose states you touch a corpse or other remains - one could argue that using the zombie statistics, the fungally infested entity is neither a corpse or remains, but an undead zombie.

However, there are also some reasonable arguments that they could work together:

• First, the Fungal Infestation does not say that the creature is undead or a zombie, but that it uses the statistics of a zombie, which might leave room for a RAW interpretation that the features could work together (for example, it could be considered a fungally infested corpse or fungally raised remains).
• Second, Gentle Repose says that it extends the time limit of raising the target from the dead and makes reference to spells like Raise Dead, which in flavour are similar to what happens with Fungal Infestation.

RAW, can a player cast gentle repose on a zombie created by Fungal Infestation?

Answer 1

No, they cannot. Per the Monster Manual p. 6 (and Rubiksmoose's comprehensive Q&A in this question more generally):

A monster's statistics, sometimes referred to as its stat block, provide the essential information that you need to run the monster.

The MM continues to describe what is included in a Monster's stat block, which on p6 includes the Monster's type.

Per the description of a zombie, the fungally infested creature is considered a medium sized undead creature. Gentle Repose only affects corpses or other remains, meaning that a creature affected by Fungal Infestation could not be affected by Gentle Repose.

Answer 2

Gentle Repose does not interact with - such as extend duration of - Fungal Infestation at all. The corpse can't become undead again, but that doesn't do anything to its current fungal zombie state. And after an hour, the fungal zombie quite explicitly collapses and dies:

remains animate for 1 hour, after which time it collapses and dies.

But this doesn't do anything for the ongoing Gentle Repose effect.

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As to argument that Gentle Repose can't target a zombie, well, the spell does not require the target to be dead. It is enough that target is "a corpse or other remains". While one might stretch an argument that a zombie technically isn't a "corpse" because it is a creature, it would still still be "other remains" of the once-living original creature.

Answer 3

You can cast Gentle Repose on any corpse

It's fine if that corpse is part of an undead creature, or a macabre decoration, or fresh, or really really old. Gentle Repose requires only 'a corpse or other remains' and places no limits on the state those must be in, beyond those inherent in the words themselves. If you wanted to Gentle Respose a fossil or something, that might be debatable, but since zombies are so iconically defined as walking corpses that shouldn't be a problem here.

You can't fungally infest a reposed corpse

Gentle Repose prevents a corpse from becoming undead. Fungal Infestation, since it gives a creature the statistics of a Zombie and one of those is being undead, makes a corpse undead. So you can't do Gentle Repose first.

You can totally Gentle Repose a fungally infested corpse

The zombie still has a corpse as part of its body, so you can totally cast Gentle Repose on that part of it. That prevents it from becoming an undead creature, which it probably couldn't already on account of already being part of one, but doesn't stop it from continuing to be one currently. It also extends the time you have to cast Raise Dead et al. on the corpse for a while, as per usual, though you will have to wait the 1 hour for the zombie to die first (or kill it yourself, or use really powerful resurrection magics).

There isn't a whole lot of reason to do this, but there isn't anything stopping you from doing it either, at least from a strict and largely favorable RAW interpretation scheme. In less favorable interpretations, Gentle Repose's "protect[ion] from decay" may well bode poorly for your fungus-controlled zombie.