I'm trying to spawn an object once another object has been destroyed how do i do that.

public class SpawnFire : MonoBehaviour { public bool iscreated = false; public GameObject Smallfire;

 void OnCollisionEnter (Collision col)
 { 

     if (col.gameObject.name == "GameFire") {
         Destroy (col.gameObject);
         iscreated = true;
     }
 }

 void update() 
     {
         if (iscreated) 
          {
             Debug.Log ("smal fire has spawned!!");
             Quaternion spawnRotation = Quaternion.identity;
             Vector3 spawnPosition = new Vector3 (
                 0, 0, -6.5f);
             Instantiate (Smallfire, spawnPosition, spawnRotation);
             iscreated = false;
          }

     }
 }