Charizard’s second mega evolution was shown during the Japanese broadcast of Pokemon Origins. The first Mega Evolution, which was shown a few weeks ago, seems exclusive to Pokemon Y.

charizard

 

This second Mega Evolution seems exclusive to Pokemon X.

char2 origins

Link

Update: Just posted the official press release and trailer. 

[expand title=”Click for full press release”] Last month it was revealed that fan favorite, Charizard, can achieve Mega Evolution, an extremely powerful form that only certain Pokémon can access during battles in the Pokémon X and Pokémon Y video games, which launch worldwide October 12 for the Nintendo 3DS. It is now known that Charizard can Mega Evolve into either Mega Charizard X or Mega Charizard Y, depending on which Mega Stone Charizard holds—Charizardite X or Charizardite Y. When Charizard Mega Evolves into Mega Charizard X, its body turns black and its flames burn blue with increased heat. It also changes types when it Mega Evolves, changing from Fire- and Flying-type to Fire- and Dragon-type!

The previously announced Mega Charizard is in fact Mega Charizard Y. Players will need to obtain Charizardite Y in Pokémon Y in order to Mega Evolve Charizard into Mega Charizard Y. Mega Charizard Y’s Sp. Attack increases significantly, and its Ability changes to Drought, increasing the power of Fire-type moves. Mega Charizard Y can learn the Fire-type move Blast Burn which becomes even more powerful with the effect of the Drought Ability.

Mega Charizard X is being introduced for the first time today. Players can obtain Charizardite X in Pokémon X and Mega Evolve Charizard into Mega Charizard X. Mega Charizard X’s Attack increases significantly and its Ability also changes to Tough Claws, which raises the power of moves that make direct contact. This Ability comes in handy when Mega Charizard X learns the Dragon-type move Dragon Tail which can force an opposing Pokémon to switch out during battle while also dealing damage.
[/expand]