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.
Rend [one-action]
Source Alien Core pg. 210
A Rend entry lists a Strike the monster has; Requirements The monster hit the same enemy with two consecutive Strikes of the listed type in the same round; Effect The monster automatically deals that Strike's damage again to the enemy.