It has been revealed that a special tournament is to take place in the Pokémon Centers. To tie in with these tournaments, and in the time around it, various Pokémon with their Mega Stones are to be distributed to players with sets aimed to help you get into battle immediately. They are all Level 50
From May 10th to May 18th, a Gyarados with Waterfall, Earthquake, Ice Fang, Dragon Dance and holding Gyaradosite is to be given
From May 19th to May 25th, a Scizor with Bullet Punch, Swords Dance, Roost, U-Turn and holding Scizorite is to be distributed
From May 26th to June 1st, a Kangaskhan with Fake Out, Return, Earthquake, Sucker Punch and holding Kangaskhanite is to be distributed
From June 2nd to June 8th, a Gengar with Shadow Ball, Sludge Bomb, Will-o-Wisp, Destiny Bond and holding Gengarite is to be distributed
From June 9th to June 15th, a Tyranitar with Stone Edge, Crunch, Earthquake, Ice Punch and holding Tyranitarite is to be distributed
Finally, from June 16th to June 22nd, a Mawile with Iron Head, Play Rough, Fire Fang, Sucker Punch and holding Mawilite is to be distributed.
Source: Serebii | Main Site