Today, The Pokémon Company announced that Mythical Island, a new expansion set featuring the pokémon Mew, is coming to Pokémon TCG Pocket on December 17th. A trailer for the expansion reveals a handful of new Pokémon cards coming to the game for the first time like Purrloin, Serperior, and Marshadow. Previously, the only way to obtain a Mew card was by collecting cards featuring each of the 150 original pokémon from the Kantonian Pokédex, but it should be much easier to snag the new…