The first images from CoroCoro have leaked and have revealed a Distribution about Shiny Poipole from March 2nd until Arpil 9th, 2018
you have to purchase special Promo Card Packs who release on March 2nd ...further informations are unknown about how to get a serialcode....
Alternative Source about the featured TCG: http://www.pokemon-card.com/products/sm/sm6.html
EDIT : This Poipole will know Dragon Pulse allowing for quick evolution into Naganadel and will be available at the following stores from March 2nd:
Aeon
Aeon Style 7-11
Tsutaya
Toys R Us
Nojima, BIC Camera, Kozima, Soft Map, Futaba Book, Heiwado, Yamada Denki, Yodobashi Camera, Wondergoo
Amazon
Rakuten and Pokémon Centers / Stores
Source: http://www.pokemon.co.jp/info/2018/02/180216_cm01.html?top_main001=msign