I just stumbled upon this guy's channel:
He takes integral existing video clips of various artists and convert the music to another style. He does himself the instruments and sometimes the voice; he can also uses samples of the original song.
For example, the video clip you will first see with the link I provided is one of Justin Bieber, but metal version! Very funny!
You can browse his entire video uploads. There's also a Disney radio version of Angel of Death by Slayer!