The monster's AI is amusing to read, and its behavior has a surprising amount of depth. Really explains its scary, clever and unpredictable nature.

It has over 15 different behavior states:

Idle, GoHome, Wait, Patrol, Investigate, Alert, Search, Eat, Hurt, Hunt, HuntPause, HuntWander, AttackMeleeShort, AttackMeleeLong, AttackRange, BreakDoor, Dead, Flee, Stalk, Track

States:

https://github.com/FrictionalGames/AmnesiaTheDarkDescent/blo...

Implementation:

https://github.com/FrictionalGames/AmnesiaTheDarkDescent/blo...

There's also naming gems like "mindfuckevents"

https://github.com/FrictionalGames/AmnesiaTheDarkDescent/blo...