Pokemon Sun and Moon players will be able to grab a Shiny Silvally from GameStop later this month
Gladion would be jelly.
Right now GameStop is in the midst of its Marshadow giveaway (which you should take advantage of while its there), but both they and the Pokemon Company are already looking ahead to the next giveaway, which was announced earlier today. Starting on October 23rd (the day that the Marshadow giveaway ends), players can grab a code card for a Shiny Silvally.
While Silvally can be had by merely playing the game and evolving your gifted Type: Null, a shiny Silvally is very tough to come by, and unless you strike gold on the first try, getting one involves A LOT of soft resets. This way, you won't have to sit through disappointment after disappointment.
Silvally itself is a unique Pokemon, particularly in tandem with its exclusive ability, RKS System. The ability allows Silvally to change its type on the fly outside of battle by giving it a memory disc to hold. The memory disc then ties into Silvally's signature move, Multi-Attack, a powerful Physical move whose type is determined by which memory disc is being held.
GameStop will be giving away the Shiny Silvally code cards from October 23rd through November 13th, so you don't have too long to take advantage of the offer.