You see through magical disguises (whether illusions or polymorph effects) of the same spell level or lower. This allows you to see the true forms of creatures magically disguised by such methods. The true form appears as a ghostly overlay on the creature’s disguised appearance.
Pathfinder Roleplaying Game Advanced Class Guide © 2014, Paizo Inc.; Authors: Dennis Baker, Ross Byers, Jesse Benner, Savannah Broadway, Jason Bulmahn, Jim Groves, Tim Hitchcock, Tracy Hurley, Jonathan H. Keith, Will McCardell, Dale C. McCoy, Jr., Tom Phillips, Stephen Radney-MacFarland, Thomas M. Reid, Sean K Reynolds, Tork Shaw, Owen K.C. Stephens, and Russ Taylor.