In Pokémon X/Y, you can customize your trainers. This is something The Pokémon Company previously revealed, but here's a good look at how dress-up works in Pokémon X/Y.
There seems to be a big game in how the characters look in this mode and in the actual game, but whatever. Not sure which is better name for this: Pokédress-up or Dress-upmon?
Pokemon X/Y - Commercials [YouTube]