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.
Shield Block [reaction]
Source Alien Core pg. 210
Trigger The monster has its shield raised and takes damage from a physical attack; Effect The monster snaps its shield into place to deflect a blow. The shield prevents the monster from taking an amount of damage up to the shield's Hardness. The monster and the shield each take any remaining damage, possibly breaking or destroying the shield.