Just judging on its appearance, did Slowbro ever look like a Psychic type? Mega evolutions bring out the latent abilities of a pokemon. Now why would a dopey, slow pokemon be a psychic type, a type that implies amazing cognitive abilities? Balancing on its tail, not only its own weight, but the weight if the Shellder that got even bigger, would require immense concentration on top of concentrating on the battle at hand.
If Mega Slowbro isn't balancing on its tail due to its cognitive capabilities finally surfacing, then it could be also explained with Slowbro's psychic abilities being so advanced, that using them to keep balance is as normal to it as breathing. If that's the case, then it brings up the question: just how far can its psychic abilities go when it can exert them so effortlessly?
It's finally acting like a proper Psychic type, and it's goofy looking mega for a goofy pokemon. Bro's good in battle, too. 10/10.
