If a simulacrum has all the statistics of the creature it duplicates, could it regenerate hit points if it has regeneration?
I understand that simulacrum can't recover hit points with healing magic or rest and that you need to spend resources to repair it. I'm curious if this is an exception.
If the simulacrum is damaged, you can repair it in an alchemical laboratory, using rare herbs and minerals worth 100 gp per hit point it regains.
First note that this does not say heal it says repair. Though treated as a normal creature it is still a being made of ice and snow. It is that reason that it likely has a special way to repair it.
This statement must preclude other forms of regaining hit points otherwise it is meaningless. Even though it does not say so explicitly, the above method is clearly meant to be the only way to regain hit points for a simulacrum.
It does not say that potions or healing magic or rest doesn't work for example, but if they were possible then the expensive complicated process for healing would be meaningless and there would be no point in including it. Sleep especially makes this meaningless because it is free and available to every creature/class and allows for healing completely. Why would anybody ever pay 100gp per hit point if they could sleep or use any of the myriad of other methods for regaining hit points available? This logic also applies to traits or features that let you heal.
Jeremy Crawford supports this logic as well:
To restore hit points to a simulacrum, you must use the costly alchemical procedure mentioned in the spell.
Also note that the creature you are duplicating must be a beast or humanoid and I could not find one of either in the Monster Manual that has regeneration. There may be ones from other sources, but it is something to be aware of.
May ping me for disagreeing with Jeremy Crawford on this. It may be intended not to be healed outside the chemical procedure but all the wording on the spell doesn't indicate this at all.
The duplicate is a creature, partially real and formed from ice or snow, and it can take actions and otherwise be affected as a normal creature.
The italicized portion implies that magical healing would work. It benefits from everything that creature could benefit from. Even the text of cure wounds starts as:
A creature you touch regains a number ...
The simulacrum spell specifically calls it out as a creature.
If the simulacrum is damaged, you can repair it in an alchemical laboratory, using rare herbs and minerals worth 100 gp per hit point it regains.
This to me only gives the creator an additional option on how to heal the creature. It does not restrict it as the only method. This statement is not pointless. Even if natural healing shouldn't work RAI, a full wizard couldn't heal the construct if this wasn't here. This just gives the wizard an option. If this was the only option, you would think that they would have included or errated that this with a simple sentence.
Generally on healing and simulacrum: Most healing spells specifically exclude undead and constructs in their wording.
Specifically regarding regeneration: There are no beasts or humanoids that possess regeneration in any 5E monster material, so its a special case that there will ever be a simulacrum with the ability to copy in the first place. As a special case/house ruled situation, it will likely require further arbitration from the DM. Based on intent then, since it isn't a situation that can happen RAW, RAI from Jeremy Crawford's tweet on the matter is that the alchemical process detailed in the simulacrum spell is the only method of repairing its hit points.
