- pierce magical concealment - complete arcane page 81
This is applied if you are attacking an enemy that became incorporeal through a spell.
Your fierce contempt for magic allows you to disregard the miss chance
granted by spells or spell-like abilities such as darkness, blur,
invisibility, obscuring mist, ghostform (see page 109), and spells
when used to create concealment effects (such as a wizard using
permanent image to fill a corridor with illusory fire and smoke). In
addition, when facing a creature protected by mirror image, you can
immediately pick out the real creature from its figments. Your ability
to ignore the miss chance granted by magical concealment doesn't grant
you any ability to ignore nonmagical concealment (so you would still
have a 20% miss chance against an invisible creature hiding in fog,
for example).
Use a spell
WHY? - Because spells have ha 50% miss chance if casted by a corporeal to attack an incorporeal, but incorporeal creatures casting a spell on corporeals have no miss chance. (not symmetric rule)
** By Feat**
- pierce magical concealment complete arcane 81
This is applied if you made yourself incorporeal through a class feature that is either (mag) or (SOP) and you attack attack someone that is corporeal