Victorious Morgana is a rare end of season reward which is no longer available.
This skin was awarded to all players who achieved the Gold tier or higher at the end of season 4. The skin is 1 of the 5 Victorious themes skins available including other champions such as Elise, Janna and Jarvan.
Released on 11th November 2014 this skin is the 2nd most recent Victorious skin released. All players that were eligible had the skin automatically added to their account at the end of season 4.
The skin features Morgana in her new Victorious blue armour with a golden trim around the edge. She also has a new helmet with golden horns sticking out.
The sounds and animations have not been changed while the particles for her auto attacks and recalls have been updated to match the theme. This is a rare skin as there is no way to obtain it now season 4 has finished.
The skin is currently not available in game as it was an end of season reward which has been and gone. If you really want the Victorious Morgana skin then the only way to get it is to purchase an account with it redeemed.