Does the victim of a Carrionette's Soul Swap, get a Carrionette's actions, when it gets control of its body?

Question

The Carrionette listed in Van Richten's Guide To Ravenloft, is given a Challenge Rating 1 (!?!) and features a pair of actions which seem very powerful:

Silver Needle. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 1 piercing damage plus 3 (1d6) necrotic damage, and the target must succeed on a DC 12 Charisma saving throw or become cursed for 1 minute. While cursed in this way, the target's speed is reduced by 10 feet, and it must roll a 1d4 and subtract the number rolled from each ability check or attack roll it makes.

Soul Swap. The carrionette targets a creature it can see within 15 feet of it that is cursed by its Silver Needle. Unless the target is protected by a protection from evil and good spell, it must succeed on a DC 12 Charisma saving throw or have its consciousness swapped with the carrionette. The carrionette gains control of the target's body, and the target is unconscious for 1 hour, after which it gains control of the carrionette's body. While controlling the target's body, the carrionette retains its Intelligence, Wisdom, and Charisma scores. It otherwise uses the controlled body's statistics, but doesn't gain access to the target's knowledge, class features, or proficiencies.
If the carrionette's body is destroyed, both the carrionette and the target die. A protection from evil and good spell cast on the controlled body drives the carrionette out and returns the consciousness of both creatures to their original bodies. The swap is also undone if the controlled body takes damage from the carrionette's Silver Needle.

This action's description says the carrionette uses the controlled body's statistics, but doesn't get the target's knowledge, class features, proficiencies, or mental (spellcasting) ability scores.

Please note that it doesn't say that the victim has any change in stats. It says the victim "gains control of the carrionette's body", but it makes no mention whether the victim's physical stats change the way the carrionette's do.

If the victims retain their own stats, they will not have resistance to Poison while in the carrionette's doll body, nor the benefit of its AC (gonna need it, with no armor on), nor will they be sustained by the wooden body's Unusual Nature. This will actually be very problematic for the carrionette, as the carrionette dies if its victim dies in the carrionette's body.

If the victim does get the carrionette's physical stats when it gains control of the Small construct's body, which stats does it get? (Does it get 15 AC? Or 13 AC? Does it get Unusual Nature? False Object?)

Most crucially (I think), is the carrionette's victim able to use either the Silver Needle or the Soul Swap actions?

Which of a carrionette victim's stats are changed (if any), while they are control of the carrionette body?

Answer 1

As this is not defined, the DM will have to make a call

As you observe yourself, the monster entry for the carionette only says the victim "gains control of the carrionette's body", but it makes no mention on being able to use its own class abilities or the carionette's stats, or if some of the carrionettes stats and actions were tied to its mind and are now not available.

With no written guidance, this will be up to the DM. I think the one thing that is clear is that the character keeps their mental ability scores and personality, because it otherwise it would not make sense to say the character had "control" of the carrionette body. Here are a few options to help a DM to consider how to handle this:

Magic Jar

One possiblity would be to look at how this works for magic jar, another soul-swapping effect which says

Once you possess a creature's body, you control it. Your game statistics are replaced by the statistics of the creature, though you retain your alignment and your Intelligence, Wisdom, and Charisma scores. You retain the benefit of your own class features. If the target has any class levels, you can't use any of its class features.

Going this route would mean that the PC would in principle keep their class abilities, and get access to all the carrionette's abilities, including the Silver Needle and Soul Swap actions. It probably would also make sense to look at other form-changing effects, like polymorph and the druid's shapechange ability (each of them, in itself a rich source of questions on this site), to further decide how to handle class abilities that the carrionette may be physically unable to perform. For example if it has no mouth, the character probably would not be able to use spells with verbal components.

This could make for a really dark gothic horror vibe, where the character can turn into a nasty gothic monster themselves and prey on innocents to get out of their predicament.

Mirror the carrionette

The carionette inherits merely the target's physical stats, but doesn't get its "knowledge, class features, or proficiencies", so anything that depends on the target's mind is off limit. As the carrionette is a monster with monster traits and actions, it has no class levels itself, and will be limited to basic actions in the new form.

You could rule that the PC likewise will not be able to use any special traits and special actions that depend on the carrionette's mind. Which those are would be up to the DM. This could for example mean that you have unusual nature, are resistant to poison, enjoy the physical stats and AC and can attack with the Silver Needle, but not curse the target, or execute a Soul Swap.

This could fit with the character's soul being trapped in the carrionette puppet, but still being themselves. They now need to seek out their former body, to undo what the carrionette has wrought, which seems to be supported by the line that the swap is undone, "if the controlled body takes damage from the carrionette's Silver Needle."

As none of this is explicitly supported by rules text, it will be up to the DM how to handle it. Tasha's Cauldron of Everything, page 4:

The rules of D&D cover many of the twists and turns that come up in play, but the possibilities are so vast that the rules can't cover everything. When you encounter something that the rules don't cover or if you're unsure how to interpret a rule, the DM decides how to proceed, aiming for a course that brings the most enjoyment to your whole group.