This was a rumored feature for sometime and confirmed by a few developers at conventions, so it does exist. They question is, How do you get it? First off, this only works in practice mode. It does NOT work online, in the challenge tower or the arcade ladder. And no, this isn't a stage you can select by hitting triangle for Stage Select. This feature or "Easter Egg" is exclusive to the Practice Mode in Mortal Kombat Vita. The video below tells you exactly how to get "augmented reality" that also features a Mortal Kombat II background that even has the MK2 birds flying in the background.
Again, if you don't want this spoiled for you, leave this page.