What if a Pokemon used Role Play on an Aegislash, and got the ability Stance Change? Would it change its stats or change form when it uses defensive or offensive moves?
Stance Change cannot be Traced, copied with Role Play, suppressed with Gastro Acid, or replaced with Simple Beam, Worry Seed, Entrainment, Skill Swap, or Mummy.
-Bulbapedia
Stance Change can't be copied, Aegislash patented it.
Source: Experience and Bulbapedia
