Pokémon Ultra Sun and Ultra Moon come out on November 17, but it looks like Game Freak still wants to keep Sun and Moon relevant right up to the release of the new games. It was recently announced on the official Pokémon website that there will soon be an event that will allow players to obtain a shiny Silvally.
The announcement explains that participating GameStop and EB Games stores will be giving out codes that can be used to receive a shiny Silvally via Mystery Gift from October 23 through November 13. Once a code is received, it must be redeemed by February 13, 2018 or else it will no longer be usable. This Silvally, like all Silvally, will have the ability RKS System, which allows it to change its type depending on what Memory Disc it is holding. It will also have the move Multi-Attack, which also changes type based on what item Silvally is holding.
According to Serebii.net, this shiny Silvally event is a replication of a shiny Silvally event that took place in Japan from September 22 to October 16. If this North American Silvally is the same as the one from the Japanese event, then we can expect the shiny Silvally to arrive at level 100 and have the moves Parting Shot, Punishment and Scary Face, as well as holding a Gold Bottle Cap.