The Evil spirit is the boss in Rum Deal. It only attacks with Melee, so turning on Protect from Melee or Deflect Melee is sufficient in protecting a player from most damage. High-levelled players should not worry about this battle, as the spirit is rather weak, has no weakness, and has few life points for its level.
The 'pun intended' comment on his examine text is a reference to a spirit, which is a type of alcohol and Braindeath rum, which is an evil alcohol.
A two-handed weapon can kill him relatively quickly. Poison is not necessary, as the spirit is immune to its effects. If a player is above level 80 and uses Protect from Melee, there is little need for food. He can only be fought once.
The Braindeath Island Brewery.
Players must have made sufficient progress in Rum Deal to be able to fight him.
Players are able to fight him when they bang their Holy Wrench on the "possessed" controls.