Magical Symphony is the name of the deck used by Shintaro Ibe, who was the champion of the Masters Division in the 2016 World Championships. It is one of the four 2016 World Championships Decks, released in November 2016, and is based around Audino. Each Deck comes with a Worlds 2016 themed Deckbox, a booklet about the championships, a code card for the Pokémon Trading Card Game Online, and the 2016 World Championships Pin. The cards included in the deck aren't the prints actually used in the decks, but are the most recent printing of the lowest rarity of the cards.
Shintaro Ito's unexpected Mega Audino-EX deck was definitely the talk of Worlds, and sure enough, this fluffy pink Pokémon proved itself worthy of a Masters Division World Champion! The Magical Symphony attack is an excellent weapon against the most popular decks, since it can Knock Out an Active Shaymin-EX plus a smaller Pokémon (like Joltik or Combee) on the Bench in a single hit. Plenty of Trainer cards for drawing and searching round out this very consistent deck!
Shintaro is very serious about tournament prep: "Before the World Championships," he says, "I would play Pokémon TCG for about 12 hours a day." Shintaro took the overseas metagame into account—he was a little nervous that his opponents would bring unfamiliar decks in an attempt to counter Night March, but he was pretty confident that his own deck, built around Mega Audino-EX, wasn't well known outside Japan. "I thought that could give me a good chance to win." Sure enough, many were surprised to see this deck when it was first played on stream—and the fluffy pink menace quickly won lots of fans!