Coming to Japan arcades in 2015, but most likely will be also coming to Wii U at a later date!
Quotes from Bulbapedia:
The official Korean Pokémon site has revealed Mega Slowbro and Mega Audino. The pages for them where taken down quickly, and are currently offline. Mega Slowbro is Water/Psychic and has Shell Armor. Its Defense and Special Attack increase greatly. It is 2.0 m (6'07") tall and weighs 120.0 kg (264.6 lbs.).
Description: Energy becomes concentrated on Shellder which is biting its tail. The result, its shell's hardness increases so that it becomes a strong armor which cannot get be scratched by anyone. When a battle begins, it uses it tail to stand upright and moves by bending its tail like a spring and springing up and down/leaping. With its greater Defense and Sp. Attack stats, it can be relied on in long battles.
Mega Audino is Normal/Fairy and has Healer. Its Defense and Special Defense are increased. It is 1.5 m (4'11") tall and weighs 35.0 kg (70.5 lbs.).
Description: It makes a healing pulse and exudes it from its body to break its enemies. This pulse of healing is strong and makes anyone feel peaceful. Anyone who comes into contact with its 2nd extension/antenna-thing falls into a deep sleep. Its increase in Defense and Sp. Defense stats make it a good supporter in Double Battles.
The next batch of CoroCoro information has been posted to Japanese forums and this batch showcases more information about the upcoming game Pokémon Omega Ruby & Alpha Sapphire.
This leak reveals Mega Altaria, who is Dragon/Fairy with Pixilate and Mega Lopunny who is Normal/Fighting with Scrappy and Mega Salamence is also confirmed and has the ability Aerilate.
It also confirms that when you change your Pikachu's clothes for contests, it gets special moves. Pikachu Rock Star gets the move Meteor Mash, Pikachu Ph. D. knows Electric Terrain, Pikachu Pop Star knows Draining Kiss, Pikachu Belle knows Icicle Crash and Pikachu Libre knows Flying Press.
Contests were also detailed. With you meeting a Contest Idol called Lucia, who will give you special clothes for participating in Pokémon Contests. You will also receive a shiny Beldum through an event, where it holds its Mega Stone