Some horrible creatures, especially undead monsters, possess a fearsome supernatural ability to drain levels from those they strike in combat. The creature making an energy drain attack draws a portion of its victim’s life force from her. Most energy drain attacks require a successful melee attack roll—mere physical contact is not enough. Each successful energy drain attack bestows one or more negative levels on the opponent. A creature takes the following penalties for each negative level it has gained. –1 on all skill checks and ability checks. –1 on attack rolls and saving throws.