Turncoat Takedown (3.5e Maneuver)

''With an efficient motion, you withdraw your knife from their leaking throat. "I'm not really Bob at all," you say gloatingly.''

Draw a weapon and attack a creature with it. That creature counts as being flat-footed against that attack, and takes an additional 5d8 points of damage if it hits. If the creature was not hostile to you, they take another 3d8 points of damage.