How to call function from another script on an instantiated Prefab?

I have a simple game where an enemy spawns, player clicks on enemy with mouse and it explodes and destroys itself, then a new enemy appears and repeats this process over and over again.

I have two scripts:

(MainScript.cs) attached to null GameObject, handles spawning and detecting the ray hit on the enemy (ExplodeScript.cs) attached to the prefab, handles the explosion and destruction of the prefab.

I am trying to use the GetComponent command to access the ExplodeScript's Explosion() method, but am getting "Null ReferenceException: Object reference not set to an instance of an object" when I click on the first enemy that spawns.

Any help would be appreciated!

Here's my code:

(MainScript)

 using UnityEngine;
 using System.Collections;
 
 public class MainScript : MonoBehaviour {
 
     Ray ray;
     RaycastHit hit;
 
     public GameObject prefab;
     public int numberOfObjects;
     public float radius;
 
     void Awake () {    
     }
 
     void Start () {
 
         // Initialize ray
         ray = Camera.main.ScreenPointToRay(Input.mousePosition);
 
            Instantiate (prefab, new Vector3(1,1,1), Quaternion.identity);
     }
 
 
     void Update () {
         ShootObject();
     }
 
 
     void ShootObject() {
 
         // Use Input.GetKeyDown() for single clicks
         if(Input.GetKeyDown(KeyCode.Mouse0))
         {
             // Reset ray with new mouse position
             ray = Camera.main.ScreenPointToRay(Input.mousePosition); 
 
             // Check to see if something got hit
             if(Physics.Raycast(ray, out hit)) {
             if(hit.transform.tag == "enemy") {
             GameObject.Find("PrefabEnemy").GetComponent<ExplodeScript>().Explode();
             Debug.Log("Enemy object HIT!");
                 }
                }
         }
       }
 }

(ExplodeScript)

 using UnityEngine;
 using System.Collections;
 
 public class ExplodeScript : MonoBehaviour {
 
     public GameObject explosion;
     public AudioClip explosionSound;
 
     // Use this for initialization
     void Start () {        
     }
     
     // Update is called once per frame
     void Update () {
     }
 
     public void Explode () {
         Instantiate(explosion,transform.position,Quaternion.identity);
         AudioSource.PlayClipAtPoint(explosionSound, transform.position);
         Destroy(this.gameObject);
     }
 }