Pardon me if I'm wrong, but isn't it impossible to catch Mewtwo (Armor) in Maps?
Here are 4 screenies of someone catching 4 variations of the pokemon in (relatively) quick succession.
http://imgur.com/aZ246EQ
http://imgur.com/hUBmZew
http://imgur.com/quOXdSY
http://imgur.com/MT8C0py