public AI _AI;
    void Start () {
  _AI = GameObject.FindWithTag("Enemy").GetComponent<AI>();
    }
    void Update () {
  RaycastHit hit;

  Debug.DrawLine(lastPos, transform.position);
  if(Physics.Linecast(lastPos, transform.position, out hit))
  {
   if(hit.collider.tag != null){
    string EnemyTag = hit.collider.tag;
    switch(EnemyTag){
     case "Enemy":
      _AI.HP -= 20;
      SpawnDecal(hit, bloodHitEffect);
     break;
    }
   }
               }