Creature Abilities
Source Alien Core pg. 208
The following creature abilities are listed here because they are shared by many creatures or are highly complex. The statistics for individual creatures might alter the traits, the number of actions, or other rules of these abilities. Anything noted in a specific creature's stat block overrides the general rules for the ability below. In these abilities, “monster” is used for the creature that has the ability, to differentiate it from any other creatures the ability might affect.
Stench
Source Alien Core pg. 210
(aura, olfactory) A creature entering the aura or starting its turn in the area must succeed at a Fortitude save or become sickened 1 (plus slowed 1 as long as it's sickened on a critical failure). A creature that succeeds at its save or recovers from being sickened is temporarily immune to all stench auras for 1 minute.