How do I prevent the destroying of all instances of an object in Unity?

I have a prefab object called Beam, which contains several things but one is an object that when an instance of it is collided with and triggered, should destroy itself.

Currently, I have the script that generates all of the instances on a variable called Beams. Shown here:

![enter image description here][1]

When that runs, it creates clones within it. Seen here:

![enter image description here][2]

You will also see in the last image, the Beam prefab that contains the Cookie in it. That cookie is where I have a script that says, if I hit it, destroy. That code looks like this:

 ...
 
 public class Collectibles : MonoBehaviour
 {
     GameManager game;
 
     // Start is called before the first frame update
     void Start()
     {
         game = FindObjectOfType<GameManager> ();
     }
 
     ...
 
     void OnTriggerEnter2D(Collider2D other) {
         if(other.tag == "Player"){
             string coinType = "Cookie";
             game.AddCollectible(coinType);
             Destroy(gameObject);
         }
         
 
     }
 }

Currently, when I run into a cookie, it runs Destroy(gameObject) and destroys ALL instances of the cookie (one per each Clone).

This code lives on Cookie, not on Beams. Is that correct? Should I have the code somewhere else? I also tried Destroy(this) but that doesn't do what I thought it would do (just the instance).

Is it possible that from where I was calling Destroy, the script doesn't have access to the instances, or am I missing something? Thank you in advance!