Wraith form, BG1 question.

Sorry about posting this here but i posted it in the tales forum, but no ones seems to be there.
I've looked about and see no mention of this spell, I found it in Durlags Tower in BG1 on the body of a greater doppleganger. has anyone else found it or was it just an odd copy of TOTSC own.
Wraithform (alteration/Illusion)
level 3
range 0
duration 2 rounds/level
area of effect caster
saving throw none
When this spell is cast, the wizard and all of his gear becomes insubstance. the caster is subject only to magical or special attacks, weapons of +1 or better, or by creatures otherwise able to effect those struck only by magical weapons. the wizard also gains a 25% magical resistance. while in wraith form the caster is unable to cast spells.
anyone?

This is one of the spells i found hex-editing in BG1, but didnt find in the game. The others were:

Polymorph other: somebody told me that he/she found it in the game, not me
Cone of cold: the same
Wraith form: i know no body who has found this one (aprat from you)
Shadow door: the enemy mages used it, but i never found a copy

Well it's nice to know it is listed some where, because it isn't listed in the manuals. As for the other i found all but cone of cold, thanks for replying.

I found the cone of cold - It's in the ulgoth's beard tavern isn't it?

I never heard of this wraith form thing until I used hex-editing.

Still - pretty strange, it must've been one of the rare spells like summon cow

(anyone remember that.......hehehe )