Maiming Strike

(Exemplars of Evil, page 25, DnD 3.5)

[General]

You can make dreadful attacks that disfigure your opponent.

Prerequisite

Sneak attack +2d6, Evil

Benefit

Whenever you make a successful sneak attack on a target creature, you can reduce your extra damage and deal Charisma damage instead. For every 2 dice of extra damage that you sacrifice, your attack deals 1 point of Charisma damage.