>>55971090>in-universeExtremely ultra-rare once-every-6-gorillion-years Bond Phenomenon where Pokemon and trainer achieve absolute sync with one another to a point where they can feel the pain of the other, but massively boosting their fighting potential because their hearts beat as one and all that cliched shonenshit.
>out of universeGameFreak's retardation in not making Mega Evolutions for Kalos Pokemon, anime mandate retardation not making an exception to the usual "Ash is only allowed to have Pikachu + Pokemon who debuted in that region" rule because this effectively meant Ash wasn't actually able to advertise Mega Evolution, the central mechanic of Kalos. So instead of discussing to loosen the rules enough to let him bring back an old Pokemon that CAN Mega Evolve, they somehow decided it was best if Mega Evolutions were crammed off into a series of specials with Alain while GameFreak vetted the creation of Ash-Greninja.
They all did this, giving Ash a special snowflake shonenfrog powerup, knowing that Ash was still slated to lose the Kalos League tournament due to further mandates that forbid him to win a league tournament, by the way.