These are used to hurt the player, the poor taffer. Simply drop it down and anything coming within its collision cylinder will be hurt. You can adjust some properties:

• DamageType - What kind of damage this thing does. Thievery uses the following DamageTypes:
  
  • KnockedOut - if this damage gets done to the back half of a player, he'll get knocked out.
    
  • Fire - the default
  • RangedArrow
  • RangedMagic
  • MeleeBlunt
  • MeleeBluntMace
  • MeleeSharp
  • Caltrop
• Damage - How much damage is done per hit
  
• DamageDelta - Time between hits.
  
• TargetClass - The class of actor that will be hurt. Anything not of this class (or subclass) can enter the ThieveryDamageActor without getting damaged.
  
• bSetFireToPawns - If set to true, any pawns getting damaged will also get set on fire.