Corrupting Touch( Ghostwalk, p. 29)
Your touch can damage creatures.
You can make a touch attack that deals 1d4 points of damage to a creature. When you are manifested fully or attacking incorporeal opponents, you add your Strength modifier to attack rolls. When you are incorporeal, you add your Dexterity modifier to attack rolls. If the attack scores a critical hit, the damage is doubled (ghosts are not subject to critical hits).
You do not have to use this ability when you touch another creature, and creatures that touch you do not take this damage.
A ghost's touch attack usually deals no damage.