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;
}

Don’t use ‘collider’ as your Collider variable name, because ‘collider’ refers to the Collider component attached to your current GameObject. Try naming it col or other. Also, be sure you don’t have this script attached to your “Zombie” GameObjects.

OnTriggerEnter(other : Collider)