Dark Sonata Corphish

[Former user]

I accidentally encountered a Corphish in the western pond of Suntouched City. It used a move called Dark Sonata, and intruiged by it, I caught the said Corphish. When I tried using the move against an opponent Audino in my Secret Base, it used the move, and Corphish transformed into the opponents Audino, copying all the moveset it had. As I tried switching out to a different Pokemon, the game screen froze but the game was still on (the D-pad was still functioning but the A B buttons weren't).

[Hansen Li]

http://pokemonzetaomicron.wikia.com/wiki/Dark_Sonata_(Move)

Seems to be in preparation for the next big patch, where all the Meloetta puzzles will be completely. There were already a ton of bugs for it in Zeta/Omicron, and somehow the wild Corphish you encountered had that move somehow.