So, the mega Pokemon were as much of a surprise to me as they were to anyone else, but really, stop and think about it for a second.

They go mega through the use of a hold item. We here on /vp/ have talked about this in the past, making a hold item that would make pokemon that aren't very usable actually good, sort of like the eviolite.

It's honestly growing on me. Think of this more as an enhance from an item rather than a new "form" or a new "stage". That's really all it is.