[Stainless Steel Devil Rat]

Damage: If the spirit or the vessel has already
sustained damage, that damage sticks around
upon successful possession, but only the greater
set of the combined Wound Modifiers applies
(modified by the spirit’s Force, for living vessels).
Physical damage incurred during possession
is recorded as a single track, and both vessel
and spirit retain the full amount of this damage
when possession ends, which is cumulative with
any previous damage. When possession ends,
the vessel’s Physical attributes return to normal
while the damage stays in place, so this damage
can have potentially lethal side effects.

1) Is the "single track" the higher CM of the two between vessel and spirit?
2) Is the "single track" the combination of both CMs?  (CM 8 host plus CM 10 spirit = CM18 on gestalt/possessed vessel)
3) What happens when the vessel has no CM (i.e. spirit is possessing a dead/inanimate vessel)?
4) Is the spirit immune to Stun damage while possessing, as the rules only refer to Physical damage?  Or does the Spirit suffer Stun damage on its own non-gestalt Stun CM?

[Kiirnodel]

1/2: The Physical Condition Monitor is based on the combined entity's (new) Body. Since a Possession spirit can augment the host's attribute it has a "new" condition monitor.

They merge bodies, so they merge damage tracks too.

For example: Force 4 spirit possesses a person with Body 3 each has Physical CM 10. The combined entity has Body 5 (base 3 plus half Force), so it now has CM 11.

3: dead bodies still have a Body Attribute so they still have a Condition Monitor. See the text about possessing inanimate vessels.

4: The spirit is not immune to Stun, its Willpower attribute doesn't change (Mental attributes remain independent). Stun damage is tracked separately between the spirit and host, so attacks at the combined entity hit both. The host or spirit (for example) could be knocked out from Stun before the other.

[Stainless Steel Devil Rat]

Thanks for the input.

...
3: dead bodies still have a Body Attribute so they still have a Condition Monitor. See the text about possessing inanimate vessels.

See this one is still giving me trouble.  I suppose the metric of "Does it have a Body Attribute?" is useful for determining what sorts of object do and do not have condition monitors.  But beyond corpses, what about objects that clearly won't have a CM?  The example on pg 197 is a spirit possessing a gun.  Say the possessed gun suffers 8 Physical damage.  It's clear that if the spirit leaves the vessel it carries 8 damage with it.

But what does 8 damage mean to a gun?  If it had a CM it'd be suffering -4 dice in wound/damage penalties.  Does someone trying to use the gun suffer that -4 penalty?  How do you know how much damage is enough to destroy the gun?  Is no Body attribute at all the same thing as a Body attribute of 0, and therefore a Gun would be destroyed since CMs start at 8 and get 1 more box for more BOD? 

I'd argue that no BOD stat at all isn't the same thing as BOD 0, as there are Drones with BOD 0 and they get CMs but things like books and trees do not.

[SunRunner]

Its one of the over sights in the system, technically I think every physical object has a damage track its just that they dont bother defining it for things that are generally not the target of direct attacks. Guns and stuff are a good example.  As for what it means thats kinda up to the GM as its just a grey area that the game does not cover as its corner case. But if you do 8 damage to a gun I can see the argument for having some dice penalties for shooting it as the sights will be messes up, the action of the gun my be impaired so its prone to Jamming as well as other things like magazine feeding issues and such that I have personally see over they years in the Army. Its just kinda something you will have to work out if it comes up. I personally have played alot of shadow run and have yet to see a gun get possessed. I will say that I am sure its happened at hundreds of tables over the years but I would also say its probably a rare occurrence in the grand scheme of things.

[firebug]

See this one is still giving me trouble.  I suppose the metric of "Does it have a Body Attribute?" is useful for determining what sorts of object do and do not have condition monitors.  But beyond corpses, what about objects that clearly won't have a CM?  The example on pg 197 is a spirit possessing a gun.  Say the possessed gun suffers 8 Physical damage.  It's clear that if the spirit leaves the vessel it carries 8 damage with it.

But what does 8 damage mean to a gun?  If it had a CM it'd be suffering -4 dice in wound/damage penalties.  Does someone trying to use the gun suffer that -4 penalty?  How do you know how much damage is enough to destroy the gun?  Is no Body attribute at all the same thing as a Body attribute of 0, and therefore a Gun would be destroyed since CMs start at 8 and get 1 more box for more BOD? 

I'd argue that no BOD stat at all isn't the same thing as BOD 0, as there are Drones with BOD 0 and they get CMs but things like books and trees do not.

Objects have Structure ratings that function similarly to the BOD attribute.  They function as Barriers  in the rules.  For the record, a gun is "Heavy Material".  As a barrier has (Structure) condition boxes for every square meter of material, a gun probably only has 2-3 boxes at most (if you rule it has more than just a piece of armored glass its size) or just 1.  Yes, this does mean it's not that hard to destroy a gun.  This is pretty realistic, as guns do need to be taken care of IRL.  I'm sure that if a gun gets hit by a bullet, people wouldn't be surprised if it was no longer safe to fire.  Granted, a lot of handguns won't be able to reliably damage eachother.

EDIT:
The text for "Break Weapon" on page 111 of Run & Gun says "Most weapons including guns are considered heavy material on the Barrier Rating table (p. 197, SR5)."

[Stainless Steel Devil Rat]

Thanks for your input firebug!  (and SunRunner... didn't mean to diss you )

A couple more questions on possessing dead/inanimate objects:

So if a spirit possesses a gun and then takes 8 damage... that sounds way more than a gun can take but the gun is not yet destroyed because it's got a gestalt CM shared with the spirit? If the spirit leaves at that point that's when the gun stops working?

In trying to research this on the forum I'm seeing references to Shedim "supposed to be having" Immunity to Normal Weapons as a matter of course through the possession ability.  I see nothing of the sort in SG... I suspect they must have been threads from before SR5... Is this a SR4 thing or is that true for SR5 as well?

[firebug]

Possession spirits in 4th Edition granted Immunity to Normal Weapons to whatever they possessed; this is no longer the case in SR5.  Possession magicians being able to give themselves Immunity via Channeling was way too OP, I think.

The way I understand the rules to work...

A F6 spirit possess a gun.  As per the rules, the spirit adds half its Force to the gun's Structure and Armor.  If this would increase the gun's CM, it does so.  Then the gun takes damage and after resists, would mark of 8 boxes.  It marks off all the boxes it can, is destroyed, and the spirit also takes 8 boxes and it forced back into the astral to find a new host.  The gun's Structure and Armor return to normal, though it's destroyed at this point so that doesn't matter.

The only way a spirit can make a vessel able to take more damage than it normally can is by modifying its defensive attributes; the gestalt CM is just a way to illustrate them sharing damage.

That said, this is just my interpretation, and I have no bits of text to back it up.  It's purely my interpretation.

However, this makes using a dead body very confusing.  How many boxes does a corpse have?  There's a difference between the amount of damage you can take before dieing than the amount of damage you can take before your body literally falls apart.  Why does a spirit get pushed out of someone as they die, but they can just jump right back in with basically no loss of capability?

[Stainless Steel Devil Rat]

...

However, this makes using a dead body very confusing.  How many boxes does a corpse have?  There's a difference between the amount of damage you can take before dieing than the amount of damage you can take before your body literally falls apart.  Why does a spirit get pushed out of someone as they die, but they can just jump right back in with basically no loss of capability?

Yeah I wasn't originally considering corpses to actually have a CM.. I was assuming the only things that had CMs are PCs and NPCs (and yes, Vehicles/drones would be NPCs!).  Clarifying that anything can potentially have a CM just changes how the dead/inanimate possession becomes confusing

Kind of starting off on a tangent now, but I presumed Shedim to basically be Shadowrun's Zombies.. given the setting is taking a hard agnostic stance on whether there's life after death or even "undead" in a sense of most fantasy RPGs.  But if a Shedim in a corpse is basically every bit as easy to kill as your average pedestrian on the street... they're seeming to fall far short of the Zombie trope standard.  That or my assumption is faulty.  I kind of like the idea for a house rule that in this specific case they'd get ItNW except for called shots (to the head, naturally).

[firebug]

Well, they're still able to use all their other spirit powers, and have magically-enhanced attributes.  Mainly though, if you look, Regeneration is an optional power for Shedim.  So basically any F3+ Shedim has regeneration, which means the corpse they're in regenerates.  Yes, that would make it look not dead in some ways.  Regeneration is basically the next-best-thing compared to Immunity to Normal Weapons.

For other SR undead though, the voudoun in Havana know how to make corps cadavre, which are basically homonculus as opposed to possessed corpses.

[Stainless Steel Devil Rat]

Well, they're still able to use all their other spirit powers, and have magically-enhanced attributes.  Mainly though, if you look, Regeneration is an optional power for Shedim.  So basically any F3+ Shedim has regeneration, which means the corpse they're in regenerates.  Yes, that would make it look not dead in some ways.  Regeneration is basically the next-best-thing compared to Immunity to Normal Weapons.

For other SR undead though, the voudoun in Havana know how to make corps cadavre, which are basically homonculus as opposed to possessed corpses.

Yeah in looking at the Shedim writeup... they can also get Aura Masking.  I guess that's probably the first thing they should have, even before regeneration.  Maybe they're more successful as a "Pod People" trope than the Walking Dead trope.