Nintendo has announced the biggest change to Pokémon's evolution mechanic since the series' inception.
Select monsters in the upcoming 3DS games Pokémon X and Y will now be able to undertake a limited-time Mega Evolution during battle, unlocking powerful new forms with altered stats and types.
Initial reaction to the new feature - leaked yesterday in early copies of Japanese magazine CoroCoro (thanks, Serebii) - has been mixed. The biggest bugbear among fans is that it bears more than a passing resemblence to the mechanics of Pokémon's longtime rival Digimon.
But there are differences - only specific Pokémon breeds will be able to Mega Evolve and only if they are in possession of the correct rare item which unlocks the ability.
For example, fully-evolved third-gen starter Blaziken will need Blazikenite - an item not usually found within the game. Nintendo will be distributing it free via Wi-Fi (along with Blaziken's unevolved form Torchic) for a limited time after X and Y's launch.
Another big series shake-up is the ability to train your Pokémon outside of battle via Super Training - touchscreen games with your squad that can raise their base stats. Your critters can also now train via themselves with Core Training, unlocked with training bags earned while Super Training.
A round-up of the new features - and another couple of new X and Y species - lies below in the new trailer.