Replace Instantiated Object

I have Instantiated 100 random objects at random locations. I want to replace each one with a smashed version on collision. I can do this with a single item on scene with with:

public GameObject myObject;

void OnCollisionEnter()
{
Instantiate(myObject, new Vector3(transform.position.x,4.3f, transform.position.z), transform.rotation);
Destroy(gameObject);
}

and adding the object to replace in the inspector. However this doesn't seem to work with Instantiated Objects as it the object to replace is not defined.

I thought I could reference the object by script with something like:
myObject = GameObject.Find("/Objects/myObject");

But everything I try returns null.

Can anyone tell me how to replace without declaring and defining a public GameObject?

 

Just figured out my error. I was assigning the smashed object to a version in the scene and hitting apply, which doesnt work. All I had to do was assign the smashed object in the prefabs folder.