As part of the Scream Fortress Very Scary Halloween Special, Valve has detailed how, exactly, the Demoman become a cyclops. A new map and boss encounter with a floating eye beast called Monoculus are the highlights, although there's new achievements and gear to grab as well.
Newer players will want to experience prior Halloween specials, since this is the one time of the year when those themed goodies are obtainable. I must acquire that Saxton Hale mask.
Here's a half hour of the Arkham Origins Mr. Freeze DLC, if you want to watch that
11:45 AM on 04.15.2014