Usually an injury from a magical creature in D&D is just a cure away from being a fond memory. However, sometimes the scars left by these wounds are sources of power in and of themselves.
You have been tainted by vampirism, and gained the ability to drink blood.
Prerequisites: Must have taken at least 4 points of Con damage* from a vampire's Blood Drain ability, character level 5th.
Benefit: If you establish or maintain a pin, you may choose to bite into your foe and drink its blood, dealing 1d2 points of Constitution damage. Because you are only partially touched by vampirism, however, using this ability also sickens you for 1 round.
A maddening gibbering persists perpetually in your mind, and occasionally surfaces verbally to assault the minds of others.
Prerequisites: Must have been affected by a gibbering mouther's Gibbering ability, character level 5th.
Benefit: You can gibber madly as a standard action, forcing all creatures other than gibbering mouthers within 30 feet to make a Will save (DC 10 + 1/2 your character level + your Con modifier) or be confused for 1 round. Each time you use this ability, take 2 points of Wisdom damage. This is a supernatural mind-affecting compulsion insanity effect. In addition, you are immune to the effects of this feat and to gibbering mouthers' Gibbering ability.
After having your body infested by xill larvae, you've become less anchored to the material plane.
Prerequisites: Must have been the target of a xill's Implant ability, character level 5th.
Benefit: Opponents have a 20% miss chance when attacking you while you are fighting defensively and a 50% miss chance while you are taking a full defense. This is a supernatural ability.
Your flesh carries the curse of death.
Prerequisites: Must have been affected by a wight's Energy Drain attack, character level 5th.
Benefit: Your unarmed strikes and natural weapons deal additional negative energy damage equal to your Charisma bonus (if any).
Yellow Musk Scion
Having had a yellow musk creeper's tendrils in your brain, you've taken on certain plant-like qualities.
Prerequisites: Must have taken at least 4 points of Int damage from a yellow musk creeper's Create Yellow Musk Zombie ability, character level 5th.
Benefit: You gain a +2 bonus on saves against mind-affecting effects (charms, compulsions, morale effects, patterns, and phantasms) and effects that cause paralysis, poison, polymorph, sleep, and stun. You also need only sleep half the usual amount for our race each night.
*Change to Con drain for D&D 3.5