Description
Here's a short video showing how to obtain the new shiny Volcanion event.
In order to get it, you need to complete the Lumiose, Hyperspace, and Mega Evolution Pokédexes in Legends Z-A and transfer them to HOME. This means every Pokémon needs to have a Lumiose origin mark, they can't be transferred in from previous games. Luckily, I already did this as the games/DLC released, so I was able to immediately get one. Since the Volcanion comes with a Lumiose origin mark, it can only be used in Legends Z-A for now.
Before, people were able to trade in order to complete specific origin Pokédexes. However, in order to complete the Mega Evolution Pokédex, you must link to a copy of Legends Z-A, so you cannot do this with this event.