When I Destroy 1 Enemy They all Get Destroyed. PLEASE HELP

So Im making a medieval Zombie game, I finished my Enemy AI, it follows the player, it has a character Controller so it wont go through walls or anything, but whenever I kill ONE zombie, ALL the other zombies die too. I think the problem is that the character controller is being destroyed but Im not sure. I need the Controller so the Zombie wont go through objects. Here is my code

 enter code here   
 var speed : float = 5;  // the speed
     
 var controller:CharacterController;
 
 static var enemyLife : int = 100; //health
 
 var Explosion : GameObject; //Explosion When Enemy is hit
 var Death : GameObject; //explosion when enemy dies
 
 
 
 
  
      
 function Start()
 {
         controller = gameObject.GetComponent(CharacterController);
          target = GameObject.FindWithTag("Player").transform; //targets the player
 
 }
 
 function Update()
 {
    transform.LookAt(target);  // the NPC looks at the player
         // Here you access the Character Controller component and move your NPC with SimpleMove() giving the speed and the direction(forward).
         //As the NPC is looking at you, forward is in your direction.
         
     
     controller.SimpleMove(speed*transform.forward); // Moves forward
     
     if (enemyLife < 1) //Death
      {
          
          Destroy(gameObject); //Destroys enemy
          var instance8 = Instantiate(Death,transform.position,transform.rotation); //Explodes
          Debug.Log("Enemy was killed");    
          
      }
 
 }
 
 
     //THIS FUNCTION IS FOR WHEN ATTACKS HIT ZOMBIE
 function OnCollisionEnter (other : Collision) 
 {
     if(other.gameObject.name == "FireBall(Clone)") //If FireBall hits it
     {
         enemyLife -=18;
         if(Amulet.EAmulet == true) //If Player has a fire amulet 
         {
             Debug.Log("EAmulet is BALLAH");
             enemyLife -= 2;    
             
         }
         Destroy(other.gameObject); 
         var instance = Instantiate(Explosion,transform.position,transform.rotation);
         Debug.Log("Enemy was hit");
         
     }
         
         
 
     else if(other.gameObject.name == "PhotonBall(Clone)") //If Photon Ball hits
     {
         enemyLife -= 20;
         if(Amulet.LAmulet == true) //if player has a light amulet
         {
             Debug.Log("Like a Diamond");
             enemyLife -= 1;
         
         }
         Destroy(other.gameObject);
         var instance2 = Instantiate(Explosion,transform.position,transform.rotation);
         
     }
 
     else if(other.gameObject.name =="Shock(Clone)")
     {
         enemyLife -= 23;
         Destroy(other.gameObject);
         var instance3 = Instantiate(Explosion,transform.position,transform.rotation);
     }
     else if(other.gameObject.name == "FrostBall(Clone)")
     {
         enemyLife -= 25;
         Destroy(other.gameObject);    
         var instance4 = Instantiate(Explosion,transform.position,transform.rotation);
     }
     else if(other.gameObject.name == "AquaBall(Clone)")
     {
         enemyLife -= 34;
         Destroy(other.gameObject);
         var instance5 = Instantiate(Explosion,transform.position,transform.rotation);
     }
     else if(other.gameObject.name == "PlasmaBall(Clone)")
     {
         enemyLife -= 35;
         Destroy(other.gameObject);
         var instance6 = Instantiate(Explosion,transform.position,transform.rotation);
     }
     else if(other.gameObject.name == "SpitFire(Clone)")
     {
         enemyLife -= 16;
         if(Amulet.FAmulet == true)
         {
             Debug.Log("FAmulet Works");
             enemyLife -= 2;    
             
         
         }
         Destroy(other.gameObject);
         var instance7 = Instantiate(Explosion,transform.position,transform.rotation);
         
     }
 }