Mildly Disturbing Halloween Mask

Overview

The mildly disturbing Halloween mask was a hat in Team Fortress 2 that was introduced to the game on October 29th 2009 as part of the Halloween update. It was unlockable only by completing the Candy Coroner achievement which involved collecting 20 of the pumpkins dropped by dead players on the Halloween event version of the map Harvest. The hat was only wearable for the duration of the Halloween event (29th October- 2nd November). According to the Valve Halloween update information these hats are "moldering, eldritch veils of such manifold depravity" and are in fact so horrifying that in self-defense the human mind will cause anyone looking at them to simply perceive them as paper bags with faces painted on them. However, the news Valve posted over their Halloween update had a general theme of humorous melodrama and so their statements may have simply been a joke over Valve trying to cheaply pass paper bags with faces painted them off as something much more scary. 
 

Variants

Despite the hat being wearable by all classes, depending on which class is wearing it, it will appear differently.