Start/End Dates	2014-12-12 through 2015-01-16
Country	Japan

Details

The official Japanese website revealed that starting on December 12th, 2014 until January 16th, 2015, Pikachu and Mega Lizardon Y would be distributed to players of Pokémon X and Y as well as Pokémon Omega Ruby and Pokémon Alpha Sapphire at all 8 Pokémon Center locations as part of the opening celebrations for the new Pokémon Center Mega Tokyo which opened on December 12th, 2014. The Mega Lizardon Y is a Alternate-colored Lizardon holding a Lizardonite Y.



Lizardon and Pikachu were distributed throughout the day on an alternating hourly cycle. Below are the times of the day each Pokémon were available at.

Mega Lizardon Y (メガリザードンY)： 10:00~11:00, 12:00~13:00, 14:00~15:00, 16:00~17:00,18:00~19:00, 20:00~21:00
Pikachu (ピカチュウ)： 11:00~12:00, 13:00~14:00, 15:00~16:00, 17:00~18:00, 19:00~20:00

Source: http://www.pokemon.co.jp/ex/pokecen_megatokyo/present/