shadow projection on an imp familiar

[x x 806]

How do you rule a shadow projection spell on an imp familiar?

-incorporeal have no natural armor bonus but familiar give a bonus , do you count it
AC = dodge +3 dex + 2 charisma + 2 size + familiar natural armor bonus
if a mage armor is cast before you count it ?

-non magical does not do damage
magicel weapon does half
but there is also

DR 5/good or silver; Immune fire, poison; Resist acid 10, cold 10

from the imp

How do you count the 50% damage , before or after the damage resistance

-Can the imp cast change shape to broke the spell or does he take the shadow form of a beast?

-The shadow is silent and the imp can cast invisibility. Is there a chance to detect it other than by magic ?

[Humphry B ManWitch]

it is incorporeal no no natural armor.

mage armor would need to be recast on it as its body would be the one with the mage armor.

you half the damage then apply the damage reduction. or resistance(for weapon damage)

change shape will not break the spell as it should still be a shadow

it would be hard to detect and invisible shadow imp but not impossible you just get bonuses

[Humphry B ManWitch]

Btw Shadow Projection is one of the spells that are on the this should be banned list as it is too powerful especially when combined with a familiar "ray of enfeeblement" and "Limp Lash"....