Finish it
rogue attack 15
Melee weapon
Requirement: wielding a light blade
Target: one bloodied creature
Attack: Dexterity vs. AC
Hit: "3[W] + Dexterity modifier damage, and ongoing 5 damage. The ongoing damage lasts until the creature is no longer bloodied."
Miss: "Half damage, and no ongoing damage."[MP:81]
Finish it is a daily power available to rogues at 15th level.