Undead caster using polymorph spells

[HappyDaze]

When a lich uses alter self to take human form, what effect does this have on it? Can it still be harmed by positive energy, or would it now be healed by it? I know it would lose it's natural armor, DR, paralyzing/negative energy touch, etc., but would it now need to eat breathe, and sleep too?

Same question as above, except the caster is a ghost. Beyond the points raised above, does it cease being incorporeal while polymorphed into a non-incorporeal form? If the form ceases to be incorporeal, then this appears to be an easy way for a ghostly caster to take on material form for a few minutes at a time. If this is true, is the strength of the form based upon the ghost's previous strength (which became "-" as an incorporeal creature)/

[Heaven's Agent]

HappyDaze wrote:

When a lich uses alter self to take human form, what effect does this have on it? Can it still be harmed by positive energy, or would it now be healed by it? I know it would lose it's natural armor, DR, paralyzing/negative energy touch, etc., but would it now need to eat breathe, and sleep too?

It takes the form of a humanoid creature, but it retains the undead type. Other than its appearance and those aspects noted under the general polymorph rules, the only thing that changes are those the spell specifically mentions: it could gain low-light vision, scent and a swim speed, provided the assumed form has them, as well as the size-based attribute bonus.

HappyDaze wrote:

Same question as above, except the caster is a ghost. Beyond the points raised above, does it cease being incorporeal while polymorphed into a non-incorporeal form?

A ghost's incorporeal ability is an extraordinary ability. Under the general polymorph rules rules such abilities are lost if they are dependent on a creature's original form. I would rule that in the case of a ghost, it is not dependent, and as such would not be lost, but that's something to be determined by your GM.

[Malignor]

"ANIMATE THREAD!"

So ignore CON bonuses as well, I'm guessing...?

[QuidEst]

Malignor wrote:

"ANIMATE THREAD!"

So ignore CON bonuses as well, I'm guessing...?

Yes. You have no Con score to bonus.