Following the information from the Pokémon Direct, the official - TopicsExpress

Following the information from the Pokémon Direct, the official release has provided new details on the Pokémon. Mega Venusaur has the ability Thick Fat, Mega Charizard has the ability Drought and Mega Blastoise has the ability Mega Launcher which boosts its moves. It also confirmed that you will need to obtain a bracelet called the Mega Ring that holds a mysterious stone called a Key Stone. The Trainer’s Key Stone resonates with the Mega Stone held by his or her Pokémon. It was also revealed that Pokémon Bank & Poké Transporter prevent hacked Pokémon from transferring and work with multiple copies of the games. Pokémon Bank, and with it Poké Transporter, for sale in Japan on December 25th for 500¥ a year with a trial until January 31st where you have to pay afterwards.