The ghost of Zepheniah Mann was introduced on October 29th 2009 as part of the Halloween 2009 event. He appears at certain points on the Halloween event version of the map Harvest, following a preset route before disappearing again. When he is nearby ghostly wails can be heard and when indoors the lights around him will flicker out as well. Any character who gets too near to him will have the word "yikes" appear over their head, appear scared and start emitting high-pitched yelps. The player will also be switched into third-person mode and their character will be unable to use weapons or jump. The ghost wears the Ghastly Gibus hat and anyone who obtains it will find is engraved with the initials "ZM". Killing an opposing player while they are under the effects of the ghost's haunting will reward you with the scared stiff achievement.
Zepheniah Mann was a rich Englishman who was convinced by his "brain defective" sons Blutarch and Redmond to buy large plots of lands in frontier America. Mann traveled to see his new land, which he dreamed of turning into large gravel pits for weapons manufacturing, but on the journey was struck down with a great number of illnesses. Upon arriving at his new land Mann also discovered that the land he bought was simply an empty and useless desert. On a piece of skin which had dropped off his body due to illness he wrote his final will and testament.
To his maidservant Elizabeth he left his estate, including all deeds, accounts and debts, his tobacco plantation and the remains of his fortune. In a photo released by Valve, Elizabeth appears very much like an announcer does in a piece of popular fan art (that later became canon...the artist, Makani, has since been hired by Valve). To his aide and tracker Barnabas Hale (ancestor of current Mann Co CEO, Saxton Hale
) he left complete control of the company Mann & Sons Munitions Concern. To his sons, Blutarch & Redmond, he left the new land they had convinced him to buy which was split evenly between them, so they would now have a reason to bicker endlessly. He also wrote in his will that he left another person something which he trusted to them the utmost secrecy in keeping, although it is not known what this thing is or who the person was. He also left a curse so that he could deliver a haunting on anyone who would use firearms near his grave, which is presumably on the map Harvest. Essentially the story of Zepheniah Mann seems to serve as an origin story for Team Fortress 2.
As of Halloween 2010, it has been revealed that his brother (?) Silas became The Horseless Headless Horsemann after death, haunting Mann Manor in a similar fashion to Zepheniah Mann on the Harvest Event map. Any user who recieved Zepheniah's "Ghastly Gibus" before Halloween 2010 got their hat upgraded to a "Ghastlier Gibus", which is darker and has a white pumpkin decoration on it to match the Horsemann's belt buckle.