From PokéHeroes Wiki
New Event Distribution
A new mega evolution has been discovered by the most experienced breeders of Emera Town: With the use of a Mega Stone, some very strong Skarmory are apparently able to perform a mega evolution.
The breeders were able to breed a bunch of mega-able Skarmory lately and are now giving them away in an Event Distribution. So what are you waiting for? Make sure to be the first trainer own a mega version of this powerful steel bird!
This Event Distribution ends on May 30th.