The phylactery of change from the Arms and Equipment Guide reads as follows:
The wearer of this item can invoke a polymorph self ability with an indefinite duration (or until the phylactery is removed, destroyed, or dispelled). A new form can be adopted once per day. The wearer can assume his natural form without limitation, however.
How does that last rule affect a wearer suffering from a polymorph effect outside of that granted by the phylactery itself? Since the item can only grant a new form once per day, it seems like this item effectively grants shapeshifter-like resistance to unwanted polymorph effects. Am I reading this correctly?
(While the Arms and Equipment Guide is for dnd-3e, the phylactery was never updated to dnd-3.5e making it legal for using in a game with minor adjustments by the DM; it's in such a game that I plan to use the phylactery.)