Sources: Dragon #312
Dragon Compendium Vol. 1
You add a dose of raw necromantic energy to your beneficial spell, making it especially effective for undead creatures.
Benefit: Any numerical bonus granted by a spell modified with this feat increases by +2 for all undead creatures it affects. This increase does not apply to factors such as range, save DC, healing, or other numerical factors relating to a spell. Only effects described as bonuses gain this benefit. A fell energy spell takes up a spell slot one level higher than the spell's actual level.