Mega Evolution is a special in-game evolution that requires a lot of things to happen. You need a mega stone for the pokemon, and a mega item. Here are all the mega pokemon, new ones are still being entered. More of the gallery will be added soon! Here is the mega evolution symbol. Mega Evolution was officially added in Generation 6. The past generations have been granted mega evolutions as well(Some more than others). Some Pokemon like Charizard and Mewtwo can have multiple Mega Evolutions, described as either X or Y.