Rad Regeneration/Fallout 3

"After an experimental treatment, intense radiation keeps your body operating at peak performance regardless of crippling injuries... right up until death. When you suffer from Advanced Radiation Poisoning, crippled limbs automatically regenerate."

Rad Regeneration is a special perk in Fallout 3.

Effects
This perk is gained after the player character exposes themselves to critical radiation poisoning (600+ rads) for Moira's Wasteland Survival Guide. This mutation is a result of Moira's experimental radiation treatment.

When irradiated with 400 rads or more, limbs will automatically regenerate in condition at a rate of a single hit point per second, including removing any crippling effects.