Help with Destroy GameObject Code

I cant figure out why this code is destroying the object with the tag Zombie rather than the object the script is on.

 #pragma strict
 var health : float;
 var BarrCooldown : boolean = false;
 
 function Awake()
 {
     health = 5;
 }
 
 function Update()
 {
     if (health <= 0)
     {
         Destroy (gameObject);
     }
 }
 
 function OnTriggerEnter(collision : Collider)
 {
     if(collision.gameObject.tag == "Zombie")
         {
             if (BarrCooldown == false)
             {
                 health -= 1;
                 StartCooldown();
             }
         }
 }
 
 function StartCooldown()
 {
     BarrCooldown = true;
     yield WaitForSeconds(3);
     BarrCooldown = false;
 }