Unliving
The creature has no Constitution score or modifier. Any DCs or other statistics that rely on a Constitution score treat the creature as having a score of 10 (+0). The creature is immediately destroyed when it reaches 0 Hit Points. An unliving creature doesn’t heal damage naturally, but a construct can be repaired with the right tools. Spells, such as make whole, can heal constructs, and magic effects can heal undead. An unliving creature with fast healing (page 153) still benefits from that ability. Unliving creatures don’t breathe, eat, or sleep. They can’t be raised or resurrected, except through the use of miracle, wish, or a similar effect that specifically works on unliving creatures.
Format: Other Abilities unliving.
Source
Alien Archive pg. 158