You embrace your deathly nature, trading your life energy for power.
Prerequisites
Benefit
You may choose to count as undead if it would be advantageous to you when resolving the effects of spells and abilities (you do not gain undead immunities unless you are actually undead).
In addition, you may drain your own life force to gain power; as a swift action you suffer a -4 penalty to your Constitution and gain a +4 untyped bonus to another ability score of your choice. Both bonus and penalty last for up to 1 minute. You may use this ability once per day for every two Monstrous Blood feats you possess. You may have only one instance of this effect active at a time.