delegate void BehaviorFunction();

public class State
{
    ...

    // The behavior is run internally by the FSM
    public BehaviorFunction behavior;
}

public class State
{
    ...
}

...

// The behavior executed is run externally by checking the current state
switch(currentState)
{
case Afraid:
    ...
}

public interface StateBase{  void onState();}public class AfraidState : StateBase{  ...  public void onState()  {    // implement behaviour  } }