Going off of the theory that cats can see shit that we cant here.. I imagine that there's some scary demon (that we can't see) under the blanket and the cat is running away each time but the dumb ass human thinks its a game and keeps throwing him on the bed. the last time he's thrown on the bed the demon is pissed and comes face to face with the cat. thus the just pissed myself look of terror at the end

found the source. http://youtu.be/kAggi3eqYhg