Cannot implicitly convert type `UnityEngine.GameObject' to `UnityEngine.Transform'

Hello,

I checked other questions and I don't understand why I receive this common error. Here are the important parts of the code :

 public static GameObject particle;
 public static GameObject clickedGmObj; 
 public static GameObject damagePrefab;
 public static GameObject healPrefab;
 
 ......
 
 void Update () {
         GameObject clickedGmObj = null;
         if(Input.GetMouseButtonDown(0))
                 {
     clickedGmObj = GetClickedGameObject();
 
 ......
 
 GameObject GetClickedGameObject()
     {
         Ray ray = UICamera.ScreenPointToRay(Input.mousePosition);
     if(Physics.Raycast(ray,out hit))
         {
     return hit.transform.gameObject;
     }
         else
         {
             return null;
         }
 }
 
 .......
 
 public void TeamCast()
     {
 var bounds = hit.collider.bounds;
     var v3 = bounds.center;
     v3.y -= bounds.extents.y;
     damagePrefab = Instantiate(particle, v3, transform.rotation) as GameObject;   
     damagePrefab.transform.parent = clickedGmObj;

And here there are all the lines / functions dealing with spawning gameobjects, saving them or altering them. Why it gives me the error for the line : damagePrefab.transform.parent = clickedGmObj;

What I want to achieve is attach the spawned particles to the detected collider in the game which is a unit, so the particle effect will follow my unit around.

Thanks