Natural Invulnerability
From AmtWiki
A form of Monster "Armor." Text from the Celestial Codex.
Description
Functions exactly like Invulnerability (above) except it may be Healed like Natural armor at the rate of one point overall per Heal ability or spell. Most creatures with this type of armor are also Amorphous (see Traits, next page).
Not to be confused with Natural Invulnerable Armor.