How does casting Animate Dead on a True Polymorphed corpse get resolved?

Question

Inspired by some similar questions and a comment on this answer, I'm curious how one might resolve the casting of animate dead on a creature who has been true polymorphed into a corpse.

The description of the true polymorph spell states:

Choose one creature or nonmagical object that you can see within range. You transform the creature into a different creature, the creature into an object, or the object into a creature (the object must be neither worn nor carried by another creature).

[...]

Creature into Object. If you turn a creature into an object, it transforms along with whatever it is wearing and carrying into that form. The creature’s statistics become those of the object, and the creature has no memory of time spent in this form, after the spell ends and it returns to its normal form.

If indeed a corpse or pile of bones could be considered an object, and the description of animate dead states:

Choose a pile of bones or a corpse of a medium or small humanoid. Your spell raises it as an undead creature. The target becomes a skeleton if you chose bones or a zombie if you chose a corpse.

Hypothetically, could a player use True Polymorph on an enemy, turn them into a corpse, and then use Animate Dead on them to turn them into a zombie?

If so, what would happen once either of the spells wears off (either from the duration expiring or loss of concentration)? How would this be resolved?

Answer 1

There's nothing stopping you.

It's pretty straightforward, really.

• You transform the creature into a corpse with true polymorph. Check. You can do that (as long as it fails or forgoes its save). It's now a corpse which, upon dispel of the true polymorph effect, will revert to being a living creature.

• You cast animate dead on the corpse. Check. The corpse is now affected by an animate dead enchantment, and functions as a mindless undead creature. It will still revert to being a living creature upon dispel of the true polymorph effect (which, among other things, will happen if it is reduced to 0 HP)

• If the resulting undead is destroyed utterly without being reverted to 0 HP, however (via an effect like disintegrate or turn undead) then the physical body is destroyed and does not revert, thus killing the original living creature. This is a fresh and novel way to kill an enemy, admittedly, but you could also have chosen to true polymorph them into an inanimate object, and left them somewhere that they were unlikely to be found.