public class randomizer : MonoBehaviour {

public void fear()
{
    int rand = Random.Range(0, 100);
    if (rand<55){
        Debug.Log("нападают");
    }
    if (rand >= 55) {
        Debug.Log("убегают");       
    }

}

}

public class enemy : MonoBehaviour {
    private Vector3 Player;
    private Vector2 PlayerDirection;
    private float Xdif;
    private float Ydif;
    private float speed;
    private float distance;
    private bool stun;
    private float stuntime;
    // Use this for initialization
    void Start () {
        stuntime = 0;
        stun = false;
        speed = 6;
    }

    // Update is called once per frame
    public void Update () {
        distance = Vector2.Distance (Player, transform.position);
        Player = GameObject.Find ("Player").transform.position;
        if (stuntime > 0) {
            stuntime -=Time.deltaTime;
                } else {
            stun = false;
                }
        if (distance < 25 & !stun) {
                        Xdif = Player.x - transform.position.x;
                        Ydif = Player.y - transform.position.y;
                        PlayerDirection = new Vector2 (Xdif, Ydif);
                        GetComponent<Rigidbody2D>().AddForce (PlayerDirection.normalized * speed);
                }
    }
    void OnCollisionEnter2D(Collision2D Playerhit){
                if (Playerhit.gameObject.tag == "Player") {
                        stun = true;
                        stuntime = 1;
                }
    }
}

Debug.Log("нападают");