I'll agree to all that. Do you have time to write a draft?
I guess so.
I'm inclined to rework the text of the
mirror image spell rather than use a "works like
mirror image except for the following changes" formula.
How's this:
Mirror Phantoms (Su): Once a day, the General can cause up to twenty illusory duplicates of itself to step out of nearby mirrors. These duplicates are illusory figments similar to the images created by a
mirror image spell. The phantoms last up to 13 minutes or until they are destroyed.
A mirror must be large enough to reflect all of the General for a phantom to step out of it. Multiple figments can step out of the same mirror if the General creates more figments than the number of suitable mirrors. Every mirror phantom must remain within X feet of all the other phantoms and the General. The General can move into and through the figments and the figments may also move through each other. When a mirror phantom separates from the General, observers can’t use vision or hearing to tell which is real and which the phantom. The figments mimic the General's actions, pretending to strike with a sword when it strikes with a sword, charge when it charges, and so on.
The mirror phantoms are AC Y. Enemies attempting to attack or cast spells at the General must select from among indistinguishable targets. Generally, roll randomly to see whether the selected target is real or a phantom. Any successful attack against a figment destroys it. The figments seem to react normally to area spells (such as looking burned or dead after being hit by a
fireball).
When the General moves, it can merge with and split off from figments so that enemies who have learned which of them is real are again confounded.
An attacker must be able to see the phantoms to be fooled. They are not affected if the General is invisible or the attacker shuts their eyes.
The General's opponents can also attack the mirrors the phantoms stepped out of. If a mirror is broken (a typical full-length mirror is AC Z, hp 1), any phantoms that stepped out of that mirror shatter into nothingness.