Object reference not set to an instance of an object

I am trying to set up a script for a rail shooter that uses raycasting for shooting instead of just cloning objects . everything worked except for when the raycast collides with the enemy it throws this error

NullReferenceException: Object reference not set to an instance of an object Player.RaycastShoot () (at Assets/Player.cs:50) Player.Update () (at Assets/Player.cs:65)

im trying to get it to run the function in a script on an enemy. or if there is an easier way to set it up to deduct health from the enemy on each hit i would greatly appreciate knowing.

 public void RaycastShoot ()
     {
         Enemy enemyObj;
         enemyObj = gameObject.GetComponent("Enemy") as Enemy;
         
         Vector3 _ray = new Vector3(Input.mousePosition.x,Screen.height - Input.mousePosition.y - 100,0);
         
         Ray ray = Camera.main.ScreenPointToRay(_ray);
         
         RaycastHit hit;
         
         if(shootTimer > 0)
             shootTimer -= Time.deltaTime;
         
         if(shootTimer <= 0)
             shootTimer = 0;
         
         if(shootTimer == 0)
         {
             if(Input.GetKey(KeyCode.Mouse0))
             {
                 shootTimer = shootDelay;
                 
                 if(Physics.Raycast(ray, out hit, 100f))
                 {
                     
                     Debug.DrawRay(_ray, transform.TransformDirection(Vector3.forward), Color.green);
                 
                     GameObject otherObj = hit.collider.gameObject;
             
                     // Part of the code that is throwing an error
                     if(otherObj.tag == "Enemy")
                     {
                         enemyObj.EnemyDmg(damage);
                         
                         print ("Hit an Emeny");
                     }
                 }
             }
         }

this is the line that is causing the error

 if(otherObj.tag == "Enemy")
               {
                  enemyObj.EnemyDmg(damage);
 
                  print ("Hit an Emeny");
               }