You can select different scripts for each monster or NPC to cover a variety of different situations. "Heartbeat" is the default behavior—what the monster does every AI update; "Notice" is what the creature does when it notices another creature; "Damaged" is what the creature does when it takes damage, and so on. As an example of how versatile the scripted behaviors can be, the programmers created a script that can make a group of monsters play tag. They run around their area, trying to stay away from whichever monster is "it." There is even a "don't tag the butcher" rule, which keeps a tagged monster from simply turning around and returning the favor.