Argamis 
My reasoning is that changeling “shapeshifting” magic is EXACTLY that (it only changes the shape, but not the mass).
If a changeling shapeshifted into a colossal being (like Dragon Lord Torch), then they would become translucid because their “physical skin” is less than 1 milimeter thick [sustained in place by active “force fields” that constantly consume energy, rather than passively by actual bones & muscles].
The opposite is the case if they shapeshift into something smaller but much more dense [like a rock, but not a boulder].
We do not know if Chrysalis was already an “arcane master” at this point in the story (she is a pseudo_alicorn by nature, so if this happened many centuries before, then she may HAD to resort to shapeshifting like any other changeling).
About “Mean Twilight”:
It is rather imposible to properly “gauge” her “true” powerlevel by just comparing it with Chrysalis, precisely because she was created from the Queen´s magic rather recently before her demise.
Whatever Chrysalis may have had at that point was re-distributed between herself, Mean Twilight & the other 5 mean duplicates [likely not in equal parts, but rather proportionally to whatever the real mane six´s powerlevel ratios were at that moment between each others].
-> Chrysalis was severely “drained” already, so even if Mean Twilight was just a “higher level unicorn” in power, it just matched her because of this disadvantage.
Silver Dis-Astḗr
Disappointing; it would’ve felt more appropriate if she just melted him/vaporized him with her magic, or some other thing.
@Background Pony #0F5CYup, called it. Now, why the hay doesn’t she just do that in the show during other fights?Judging from how they generally seem to revert when or right after they take damage (Ocellus causing destruction accidentally by slamming into something, Pharynx being hit by the Maulwurf, Chrysalis being slammed into a rock from the wind, Thorax being undisguised from being hit by Chrysalis, a changeling losing its disguise from being blasted by Twilight, probably other examples), I strongly suspect it’s the case that there’s a great disadvantage in that their durability doesn’t increase much whenever you do that, so if they turn into a dragon, they’re not anywhere near as durable as a real one, so at best, they’re a glass cannon.It’s also not like they can from anything we see cast magic in a shapeshifted state unless they’re wearing a pony skin, and even if they could, the previous disadvantages still apply, it probably burns up more energy to sustain it, and they’re a bigger target to have injuries inflicted upon to then lead into “forcibly reverted”, so there’s really not much benefit if any benefit in fighting alicorn-level or powerful unicorn threats, to shapeshift into a bigger target. Even say, Rainbow Dash/insert skilled pegasus would only be benefitted by her going to a giant form, because she gets to fly circles around her now slower self, and she cannot perform ranged attacks like she can normally.Plus, for the character reason, aside from those considerations, Chrysalis seems to like throwing magic around in a flashy manner at the first opportunity whenever she’s in a position of power, as opposed to relying on shapeshifting, especially considering she’s at master/expert unicorn levels of arcane power at absolute worst, no love boost, depending on if Mean Twilight (slightly stronger and/or was more innately skilled) was alicorn level, unicorn level, or in-between.
My reasoning is that changeling “shapeshifting” magic is EXACTLY that (it only changes the shape, but not the mass).
If a changeling shapeshifted into a colossal being (like Dragon Lord Torch), then they would become translucid because their “physical skin” is less than 1 milimeter thick [sustained in place by active “force fields” that constantly consume energy, rather than passively by actual bones & muscles].
The opposite is the case if they shapeshift into something smaller but much more dense [like a rock, but not a boulder].
We do not know if Chrysalis was already an “arcane master” at this point in the story (she is a pseudo_alicorn by nature, so if this happened many centuries before, then she may HAD to resort to shapeshifting like any other changeling).
About “Mean Twilight”:
It is rather imposible to properly “gauge” her “true” powerlevel by just comparing it with Chrysalis, precisely because she was created from the Queen´s magic rather recently before her demise.
Whatever Chrysalis may have had at that point was re-distributed between herself, Mean Twilight & the other 5 mean duplicates [likely not in equal parts, but rather proportionally to whatever the real mane six´s powerlevel ratios were at that moment between each others].
-> Chrysalis was severely “drained” already, so even if Mean Twilight was just a “higher level unicorn” in power, it just matched her because of this disadvantage.
