Creatures with this extraordinary ability recover from wounds quickly and can even regrow or reattach severed body parts.
Damage dealt to the creature is treated as
nonlethal damage, and the creature automatically cures itself of
nonlethal damage at a fixed rate.
Certain attack forms, typically fire and acid, deal
damage to the creature normally; that sort of
damage doesn't convert to
nonlethal damage and so doesn't go away. The creature's description includes the details.
Creatures with regeneration can regrow lost portions of their bodies and can reattach severed limbs or body parts. Severed parts die if they are not reattached.