Much like his pal Mewtwo, it turns out Charizard will have different Mega Evolutions depending on which version of Pokémon X & Y you are playing.
The previously revealed Charizard Mega Evolution is the Y version, while the new black and blue Charizard (see above) is the Mega Evolved Charizard you will find in X. Game Freak and Nintendo made no mention in regard to whether or not the other starters, Squirtle, and Bulbasaur, will have separate X and Y Mega Evolutions.
Pokémon X & Y are coming to Nintendo 3DS on October 12. You can check out the trailer showcasing Mega Charizard X below, as well as more images of the Mega Evolved Charizards in the image gallery.