Behaviour
Defines how an Actor moves etc.
An Actor's behaviour can change, the classic example is Pac-Man ghosts : At first they are trying to catch Pac-Man, but when a power-pellet is eaten, they change behaviour and flee.
You could implement this ghost-like behaviour with a big if in a single Behaviour, or have one Behaviour for chasing, and another for fleeing. Set Actor.behaviour when a power-pellet is eaten, and reset it when it wears off. I prefer the latter, YMMV.