NullReferenceException when instancing GameObject

[unity_LnADOc9dQB4dYA]

I’m trying to use the Instance() command to spawn a GameObject but I get weird results. The first time I place the object into the GameObject public variable, the object spawns fine, but the second time, and each one after, the console prints out NullReferenceException: Object reference not set to an instance of an object. The problem seems to come from the Update method in this script:

public class ResourceScript : MonoBehaviour, IOnClick
{


    public Text materialCounter;

    public void OnClickAction()
    {
        GameManager.material += GameManager.multiplier;
        PlayerPrefs.SetInt("material", GameManager.material);
    }

    /*private void MiningMechanic()
    {
        if (miningPoints > 4)
        {
            Destroy(solidMaterial);
            Instantiate(crackedMaterial, Vector3.zero, Quaternion.identity);
            miningPoints++;
            Debug.Log("You have" + miningPoints + "miningPoints");
        }
    }*/


    private void Update()
    {
        materialCounter.text = "Rocks: " + GameManager.material;
    }
}

Also, here is the script I use for spawning objects:

public class Spawner : MonoBehaviour, IOnClick
{
    public GameObject solidMaterial;
    public GameObject crackedMaterial;
  
    int miningPoints = 0;

    void Start()
    {
        Instantiate(solidMaterial, Vector3.zero, Quaternion.identity);
        solidMaterial.AddComponent<ResourceScript>();
        //solidMaterial.AddComponent<Text>();

    }
  
    public void OnClickAction()
    {
        MiningMechanic();
        Debug.Log("MiningMechanic Activated");
    }

    private void MiningMechanic()
    {
        if (miningPoints > 4)
        {
            Destroy(solidMaterial);
            Instantiate(crackedMaterial, Vector3.zero, Quaternion.identity);
            miningPoints++;
            Debug.Log("You have" + miningPoints + "miningPoints");
        }
    }

}

This is how it looks the first time I spawn a Prefab

And this is the second time

However, after the error starts appearing trying to instance the Prefab even inside of the most basic instancing script prints out the same error:

public class Test : MonoBehaviour
{
    public GameObject solidMaterial;

    // Start is called before the first frame update
    private void Start()
    {
        Instantiate(solidMaterial, Vector3.zero, Quaternion.identity);
    }

}

Does anyone have a clue why this is happening?

[Admartimus]

I think the issue is that with the destroy you destroy the source gameobject not the one you created. So beside the reference you have to the prefab you need a variable holding the instantiated prefab which you can later destroy.

Can you see that the prefab field in the inspector is going from your prefab to empty?

[QuentinBacuet]

I’m guessing that the problem comes from materialCounter in ResourceScript. Are you sure this is not null and that it is properly initialized?

I would advise you to use initialize the text directly in the prefab by adding the script to the prefab through the Unity UI and not within your scripts.