Enervating Shadow

Warlock Invocation
Level: Greater, 5th lv.
Components: V, S
Casting Time: 1 standard action
Range: Self, adjacent creatures
Duration: 5 rounds
Saving Throw: Fort
Spell Resistance: No

The dark powers cloak and shield you while draining vitality of foes. You gain total concealment in any place that is not brightly lit (it wont work in daylight or in the radius of any spell with the light descriptor.) Any living creature adjacent to you makes a fort save at the beginning of its turn or take a -5 Str penalty for 5 rounds. A creature cannot be affected more than once for 24 hours. The duration of this effect is 5 rounds and can be dispelled by any light spell or effect of equal or higher lvl.

(Complete Arcane, Page 134)