My first pass was IFT() for incorporeal, then make the DMGTYPE into force, but DMGTYPE is not targetable. Every other scheme I can think of involves players remembering to turn effects on and off or they will bypass DR on corporeal creatures. Ideally I would love to see a ghost damage type and modifier on armor that would interact with incorporeals. Does anyone have suggestions on good ways to set this up as the PF ruleset is now?