Fans of deadmau5 know who this cat is; this is Mr. Meowingtons, the producer's cat. He's been the subject of a number of videos on YouTube, and is pretty fond of bass:

Perhaps unsurprisingly, there's an entire Tumblr devoted to the cats of some of your favorite producers, with the pets of Wolfgang Gartner, Alana Watson (Nero), and Elhornet (Knife Party) all being represented.