The Bear
Currently my favorite interaction the AI guys are playing with happens between mother bears and their cubs. Mother bears are aggressive, but have a relatively small area of interest. Cubs on the other hand aren't aggressive but are very curious. If a cub detects a player it will head over to investigate, and if they actually reach the player to finish their investigation or are attacked by the player they cry out to Momma in alarm and she comes running. She is, of course, none to happy with you so near her baby and fights with a rage only a mother would understand. This rage state only happens when a cub is involved.
This
quote from developer Hakai promises some interesting developments in mob AI.
Pre-blackout Screenshot