Using animations in prefabs

I have a floor made out of cubes. And when the player moves around, random boxes around him animate and scale up. I'm trying to do this with a prefab. The problem I'm facing is that, when the player moves around, the animation works. But it always happens to the first cube (the first prefab I created). How can I have that animation for the random cube that's been selected and not the first cube always?

This is roughly what I'm doing:

 var tileArray : GameObject[];
 var nodes : Array;
 
 var speed : float = 5;
 var x : float;
 var z : float;
 
 var tile : GameObject;
 
 function Start () 
 {
     InvokeRepeating("LiftRandomTile", 0, 1);
 }
 
 function Update () {
     x = Input.GetAxis("Horizontal") * speed * Time.deltaTime; 
      z = Input.GetAxis("Vertical") * speed * Time.deltaTime; 
      transform.Translate(x, 0, z); 
 }
 
 function OnTriggerEnter (other : Collider) {
         tileArray += [other.gameObject];
 }
 
 function LiftRandomTile () {
     if (tileArray.Length > 0)
     {
         Debug.Log("Nodes " + nodes);
         tile = tileArray[0];
         //tile.transform.position.y += 5;
         tile.animation.Play("Floor Animation");
     }
     tileArray = new Array();
 }

Thanks.