...is totally broken.

I mean, Groudon and Kyogre just need to be holding their Orbs in order to undergo Primal Reversion, and even if they get knocked out, if you can revive them, sending them out again will make them go through Primal Reversion again. And you can have them AND a Mega Evolution in the same battle!

And Mega Rayquaza...dear lord. All it needs to Mega Evolve is the move Dragon Ascent. This means it's free to hold a Choice Band, or if you prefer the ability to switch between moves and don't mind the recoil damage, a Life Orb.

Yeah. What will they come up with next?

A new type of special evolution.

3832263 Or Mega Arceus, with the ability to change its type in the middle of a battle.

3832275 Ehh….That'd be OP.

3832546 Exactly.

3833234 Personally I would like to see Mega-Slacking with huge power.

Just imagine Mega-Miltank.

3833764 Of course, Mega Slaking would no doubt have a Super-Truant ability, where it can only move once every four turns.

And that Mega Miltank picture...it looks gross.