How can I instantiate a gameobject facing another gameobject 2D?

I'm currently working on an arcade style game. I need one of the enemies to shoot at the player (in the direction of the players current position in 2d) however I'm having trouble getting the bullet/ laser to instantiate facing the player. T$$anonymous$$s is my current code:`

public class AlienGunScript : MonoBehaviour {

 [SerializeField]
 Quaternion defaultRotation = Quaternion.identity;
 [SerializeField]
 float gunRotSpeed;
 public GameObject target;
 public GameObject Alien;
 public Vector2 localPos;
 public GameObject laser;
 public Vector3 maybe;
 void Update()
 {
     //Rotate towards the player
     Vector3 dir = target.transform.position - transform.position;
     dir.Normalize();
     float zAngle = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg - 90;
     Quaternion desiredRot = Quaternion.Euler(0, 0, zAngle + 90);
     transform.rotation = Quaternion.RotateTowards(transform.rotation, desiredRot, gunRotSpeed * Time.deltaTime);
 }
 void FixedUpdate()
 {
     transform.position = new Vector3(Alien.transform.position.x + localPos.x, Alien.transform.position.y + localPos.y,0f);
 }

 public void shootLasers()
 {
     Instantiate(laser, transform.position,Quaternion.identity);
     Debug.Log("shot");
 }

}` You can ignore the code in Update and Fixed Update as that is for moving the alien sprite t$$anonymous$$s script is attached to. The problem area is in shootLasers where I'm not sure what to put for the t$$anonymous$$rd rotation parameter. Does anyone know how to find the rotation of a gameobject facing another gameobject in 2d? Sorry for my bad English, thanks for any help.