The Brain Hat, in lovely soft merino. Well, brains are supposed to be soft, aren't they? And washable? You don't want your brain to shrink or felt in the brainwash, of course!
Thus we have the perfect accessory for the Zombie Apocalypse--when being chased, you whip off your knitted brains, fling them at the pursuing zombies, and make your escape. And a zombie can keep its head warm: