Searching an ArrayList of Instanced Prefabs possible?

Unity Engine
1

Hello everyone!. I have this little script that, with declarations and stuff ignored, SHOULD, change the color of a prefab, instance it, add it to an ArrayList and then print the colors of every object in the array list.
My problem is that, when I instance them and add them to the list, all is good, but when I search its colors, the instanced objects all gave NullReferenceExeption.

I was hoping someone could look at it and spot something im missing here.
Thanks in advance!

void Start () {
      timer = 0; 
       ballList = new ArrayList(); 
}

     void Update () {
 
        timer += Time.deltaTime;
        if (ballList.Count < 10)
         {
            if (timer > 0.5)
            {
                RandomizeColors(ballPrefab); //randomizes and assigns a material.
                clone = Instantiate(ballPrefab, transform.position, transform.rotation) as GameObject;
              lista.Add(clone);
                timer = 0;
            }
        }
        else
        {
            foreach (GameObject ballz in lista)
            {
                Debug.Log(ballz.renderer.material.name); //NULL REFERENCE EXEPTION
                //here goes the code that searches for balls of the same color and deletes
 them           
              }
        }
 
    }
2

SOLVED im dumb as a wall can be

3

Also why you using an ArrayList, a type array (ie GameObject[ ]) or a Generic List is better.