Magnagate
A Magnagate is a portal to a Mystery Dungeon that can be found by scanning a round objects in the real world. Dungeons found in Magnagates vary by color of the object scanned, and vary in hardest based on size of the object. Dungeons found by Magnagates are played like normal dungeons, but you may be able to play as Pokémon different from your own leader and parter. At the end of Magnagate dungeons you must fight the dungeon's leaders, who are generally more powerful than the others in the dungeon. Money and items received in these dungeons will be sent back to your save file.
Special Pokémon
Some Pokémon can only be found in Magnagate Dungeons, appearing only in specific dungeons.
Lugia and Ho-oh are examples of this.
In the demo
In the demo released for the Nintendo eShop on March 7, Magnagates also make an appearance. When scanned the demo doesn't take size or color into account. Instead the player is sent to a random Magnagate Dungeon.