Can someone please tell me what rap song this is towards the end of this movie trailer?

Starting at :50 seconds into the trailer....I have looked and looked and looked and since 2006 or before no one on the entire internet has been able to identify this song. I have used SoundHound on my cell phone, every lyric website and Google search I can think of and I have had NO luck. There doesn't even seem to be a Soundtrack for this movie! HELP!