Update (10/10/2016): This Pokemon is being given out via Mystery Gift for this month only. Get this Pokemon while you still can. Thank you Twitter user @MBAfif for pointing this out to me via twitter response. 
Update 2 (10/10/2016): This is not being given away via Mystery Gift but rather at ‘participating retailers’ from Oct. 10th – Oct. 31st. 
This legendary Pokemon is being give away to 3DS owners with a copy of Pokemon X & Y or Pokemon Omega Ruby & Alpha Sapphire. He is a great looking Pokemon and recommend you download him if you have any of those listed 3DS Pokemon games.