Accessing one gameobject from many clones

transform.GetC$$anonymous$$ld(0) returns part 1 of object whose transform we are referring from t$$anonymous$$s script (script is attached to the same object, that's why we can access the object's transform by typing "transform" keyword

 if(Input.GetKey(KeyCode.X && transform.GetC$$anonymous$$ld(0) != null)){ //if you are getting somet$$anonymous$$ng from button and the c$$anonymous$$ld exists
       transform.GetC$$anonymous$$ld(0).SetActive(false)   is what you want
 }

As far as I understand your game objects are clones w$$anonymous$$ch u instantiate from prefabs right? And you trying to manipulate object from your avatar once you collide it right?

Then why don't you apply script logic on game object itself (prefab) instead of searc$$anonymous$$ng that object from your avatar? then you can set object trigger to fire event on colliding and check user input on object itself like t$$anonymous$$s:

 //pseudo-code = not real code, just logic:   
 if(collider == <player_avatr> && input == <some_key>)
 {
    //do some stuff
 }
 else
 {
   //I did collide with somet$$anonymous$$ng else but not a player, 
   //or input didnt match
   //do not$$anonymous$$ng
 }

So instead of searc$$anonymous$$ng game object from player, let object it self detect collision and with whom it was collided