Nameless Mist

The Nameless Mist was a being who's aim was to revert the univese back to the state it was before creation. The Twelfth Doctor described it as the opposite of the Big Bang. It wanted to do this because it hated the noise that the Big Bang created. The Doctor was able to use this flaw to defeat it by amplifying the music of Cold Steel through the TARDIS to make it leave his dimension for good. (COMIC: The Big Hush)