Soulreaving Aura

Warlock Invocation
Level: Least, 2nd lv.
Components: V, S
Casting Time: 1 standard action
Range: 10 feet
Area: 10 feet radius emanation, centered on you
Duration: Instantaneous
Target: Creatures with less then 0hp
Saving Throw: None
Spell Resistance: Yes

This invocation deals 1 point of damage to every creature in the area that has 0 or fewer hit points. Stable creatures that were at -1 to -8 hit points become dying, while creatures at –9 hit points die immediately. This spell has no effect on creatures that have 0 or more hit points.
In addition to the normal effect, if any creature within 10 feet of you dies, you gain temporary hit points equal to its HD (maximum 10) for 1 round.

(Complete Mage, Page 124)