Stolen vitality
rogue attack 19
Melee weapon
Requirement: wielding a light blade.
Target: one creature
Attack: Dexterity vs. AC
Hit: "4[W] + Dexterity modifier damage, and the target is slowed (save ends). You gain temporary hit points equal to 10 + your Charisma modifier."
Miss: "Half damage, the target is slowed until the end of your next turn, and no temporary hit points."[MP:83]
Stolen vitality is a daily power available to rogues at 19th level.