Black Swan

Phenomenal performance by Natalie.  I believe the killing/stabbing was symbolic. Though Nina thought she was battling another dancer she instead was fighting herself. When Nina is fighting her biggest rival/enemy she is fighting herself. That’s why the other dancer appears to be Nina and she instead stabs herself. She is her killing the white swan. The white swan embodying the innocence that held her back from fully turning into the black swan. Only when she reappears as the white swan in the final act her injury is shown. Her physical wounds were a mere metaphor for her innocence and her doubts in herself. The death of the white swan, which held her back, was necessary, in order of becoming the black swan. This movie might also be the pendant to Whiplash (2014).