The Change Shape feature of an adult gold dragon reads as follows:
Change Shape. The dragon magically polymorphs into a humanoid or beast that has a challenge rating no higher than its own, or back into its true form. It reverts to its true form if it dies. Any equipment it is wearing or carrying is absorbed or borne by the new form (the dragon's choice). In a new form, the dragon retains its alignment, hit points, Hit Dice, ability to speak, proficiencies, Legendary Resistance, lair actions, and Intelligence, Wisdom, and Charisma scores, as well as this action. Its statistics and capabilities are otherwise replaced by those of the new form, except any class features or legendary actions of that form.
Emphasis mine. In particular, the dragon changes all of its statistics except those listed as retained, and CR is a statistic. This means that if it polymorphs into a beast, then it becomes a beast with a CR of the form that it chose and its other statistics, except those listed as retained in the adult gold dragon's Change Shape feature (including that action).
Now, that's quite a mouthful, but the important parts are that the dragon is now an instance of a type of creature which is:
- A beast
- Has the CR of some beast (up to 17)
- Has the adult gold dragon's Change Shape action, which would allow it to assume the form of an adult gold dragon
You might see where this is going. Looking now at the Druid's Wild Shape feature:
...you can use your action to magically assume the shape of a beast that you have seen before.
and later:
Your game statistics are replaced by the statistics of the beast, but you retain your alignment, personality, and Intelligence, Wisdom, and Charisma scores. You also retain all of your skill and saving throw proficiencies, in addition to gaining those of the creature. If the creature has the same proficiency as you and the bonus in its stat block is higher than yours, use the creature's bonus instead of yours. If the creature has any legendary or lair actions, you can't use them.
So, assuming that the Druid has seen an adult gold dragon use its Change Shape feature to assume the form of a beast which abides by the limitations of Wild Shape for the level of the Druid in question:
Can a Druid use Wild Shape to assume the form of a beast which has the Change Shape feature of an adult gold dragon?
More specifically, are there any rules which draw a distinction between the creature described above and a (valid-for-Wild-Shape) beast in the Monster Manual (or other source book) which mean that they should be treated differently in any way which precludes such a use of the Wild Shape feature? Potential ideas include:
- A rule which differentiates a creature with a stat block from the 'inherited' form of another
- Any rule which refers to the interaction of these features (or a similar situation) which has not been mentioned
- Errata which changes parts of the listed features such that the desired outcome is not possible
Note that this question is not a duplicate of this question, which asks about assuming the form of a particular instance of a creature: the question is whether Wild Shape can be used to assume the form of a creature which has the statistics described.
An answer which calls directly to the intent of the Wild Shape (or Shape Change) feature(s) is not useful to this question: I think it's quite clear that this is not an 'intended' interaction. What we're looking for here are rules which help us pin down how the aforementioned game systems operate and interact if they are to be taken how they are written.
