http://www.siliconera.com/2013/10/08/pokemon-x-pokemon-y-battles-faster-tougher/>"As for features completely new to battles in Pokémon X and Y, there aren’t many. There are the Mega Evolutions, which are a temporary evolution that can be activated in the middle of battle. When a Mega Evolution is available, you’ll see a button on the bottom screen alerting you. These Mega Evolutions grant a variety of power boosts such as type changes, stat increases, and ability changes. The Evolution activates the turn you press the button, and after you press it, you can also select an attack. Both actions will take place on the same turn, so the timing of your Evolution can be important.">The Evolution activates the turn you press the button, and after you press it, you can also select an attack. Both actions will take place on the same turn, so the timing of your Evolution can be important.Mega-Evolutions do NOT use up the turn you decide to use them on. So people can stop acting like Mega-evolutions will give people a chance to switch out.
