Does an attack with Psionic Weapon Feat inflict extra damage to undead?

Question

In the Expanded Psionic Handbook there's a feat (Psionic Weapon) that allows a character to expend his psionic focus before making an attack so that if he hits there is extra damage. The kind of damage isn't specified so I don't know if it can affect undead, both intelligent and non-intelligent ones. In fact, since undead are invulnerable to mind affecting effects, if the damage would be psychic then perhaps at least the non-intelligent ones wouldn't suffer from the extra damage.

Does someone know from both RAW or RAI if this feat could be useful even against undead?

Answer 1

If it doesn't specify a damage type and doesn't specify that it's [Mind-Affecting] then it's just normal damage. It'd work against undead, and it'd even work against doors and walls or whatever if you really wanted.

In this case, you're probably psychically altering the density of your weapon at the right moment to add more damage on impact, or using telekinesis to make it swing faster, or using psychometabolism to make yourself momentarily stronger, or any other explanation you care to use based on your primary psionic school (assuming you're a psion at all).

Answer 2

I would rule it in the same was as the various crystal attack powers. Which do "unspecified" damage, but footnotes indicate they are treated as their base damage type. A crystal attacking power provides no special saves, and is typically treated as slashing damage, for instance. That makes it subject to damage reduction, but not power/spell resistance.

Psionic Weapon is the same way. Although many instinctively think "telepathy" with psionics, it could just as easily mean "force", which actually works quite well against incorporeal undead like ghosts.

So the psionic weapon is not the same as sneak attack, which undead are immune to, nor is it the same as telepathic damage, which undead are immune to. It's not quite Force damage, which even targets incorporeal monsters, so it's best thought of as "you swing faster/harder" like Lokathor said.