This is not fake. This is 100% confirmed.
CoroCoro magazine confirms "mega" forms of certain Pokemon (most famously Mewtwo).
And here's some new Pokemon
I honestly don't know how to feel about this. I've been 100% on board with every change so far; the change to 3D, sky and water battles, hoard battle, etc. This just raises so many questions. Does every Pokemon have a "Mega" form? If not, why some and not others. How is the Pokemon changed when they change to Mega? Are there base stats raised? do they gain extra abilities?
**Turns out it's an in battle other form, not an actual evolution. You have your pokemon hold a special held item, and in battle it'll take its mega form. It provides a small boost to all base stats, but not as much as a specific stat increasing item**
October just can't get here fast enough.