I'm building a Lamia Matriarch as a recurring villain (monstrous humanoid, shapechanger subtype) who is capable of changing into a fixed medium-sized humanoid form, and its entry (shown here) suggests that the effect is akin to Alter Self spell.
So, what happens when she changes to that humanoid form, assuming the form is that of a normal human? Obviously the size modifiers come into play and she loses her special modes of movement, but what else? Does she lose her Darkvision? Does she lose her +8 natural armor bonus to AC? How are her attributes affected - does she simply gain +2 to Dexterity the way a medium creature shifting to small does with an Alter Self spell, or is it determined by some table somewhere defining modifiers when a creature changes size (like Reduce Person does)?
The character will be spending the majority of her time in her human form and the first two times the PC's encounter her/battle her she will be in that form only so any help would be appreciated.
I believe you want the polymorph rules.
[...]
If a polymorph spell causes you to change size, apply the size modifiers appropriately, changing your armor class, attack bonus, Combat Maneuver Bonus, and Stealth skill modifiers. Your ability scores are not modified by this change unless noted by the spell.
[...]
While under the effects of a polymorph spell, you lose all extraordinary and supernatural abilities that depend on your original form (such as keen senses, scent, and darkvision), as well as any natural attacks and movement types possessed by your original form.....
[etc]
The size modifiers table is at the end.
I think the natural armor bonus is due to her scales, so unless she is a scaly human she should probably lose that as well.
Thank you both for your responses - its between these two sets of rules that I'm getting confused.
I was leaning towards the Monster Rules, but the addition of the 'Alter Self' spell in the entry after Shapechange threw me off. So the Lamia Matriarch's ability functions as the Alter Self polymorph spell, except for the attribute changes listed therein and she does not change any attributes despite reducing size as shown on the Polymorph rules?
If a polymorph spell causes you to change size, apply the size modifiers appropriately, changing your armor class, attack bonus, Combat Maneuver Bonus, and Stealth skill modifiers. Your ability scores are not modified by this change unless noted by the spell.
While under the effects of a polymorph spell, you lose all extraordinary and supernatural abilities that depend on your original form (such as keen senses, scent, and darkvision), as well as any natural attacks and movement types possessed by your original form.
You'd have a -4 to STR, +2 to DEX and -2 to CON, but you'd gain +2 to STR because of the Alter Self effect, so you'd have only a -2 penalty to STR.
EDIT: Ninja'ed. D'oh!
Does she lose her +8 natural armor bonus to AC?Debatable. Depends whether you think it's an "ability that depends upon her original form." Also debatable is whether she can keep her spell resistance, her immunity to mind-affecting, and her Wisdom drain.
I would say that she loses the natural armor bonus, but retains the other abilities since they would not normally be defined by anything physical (like scales or a tail).
I know GM's discretion always rules... perhaps I should simply reduce it, by half, maybe?
I didn't see in polymorph spells anything specific about keeping or losing the natural armor while polymorphed (I might not have looked enough, anyway) but IMHO it would count the same as a extraordinary or supernatural ability, so you'd lose it.
Often natural armor comes from thick skin, scales, a carapace, etc. You lose that when you polymorph.
Does she lose her +8 natural armor bonus to AC?Debatable. Depends whether you think it's an "ability that depends upon her original form." Also debatable is whether she can keep her spell resistance, her immunity to mind-affecting, and her Wisdom drain.I would say that she loses the natural armor bonus, but retains the other abilities since they would not normally be defined by anything physical (like scales or a tail).
I know GM's discretion always rules... perhaps I should simply reduce it, by half, maybe?
Wisdom drain is Su. The rules for polymorph spells state that she'd lose all Su.
SR and Mind-affecting immunities are untyped so she'd retain them.
She'd also retain all her Spell-like abilities.
Does she lose her +8 natural armor bonus to AC?Debatable. Depends whether you think it's an "ability that depends upon her original form." Also debatable is whether she can keep her spell resistance, her immunity to mind-affecting, and her Wisdom drain.I would say that she loses the natural armor bonus, but retains the other abilities since they would not normally be defined by anything physical (like scales or a tail).
I know GM's discretion always rules... perhaps I should simply reduce it, by half, maybe?
Wisdom drain is Su. The rules for polymorph spells state that she'd lose all Su.
SR and Mind-affecting immunities are untyped so she'd retain them.
She'd also retain all her Spell-like abilities.
That helps too. Thanks.
Hmmmm... Good point.