How to destroy a gameobject on collision

The OnCollisionEnter function of a GameObject is called whenever another collider hits your GameObject, as long as one of them has a rigidbody.

What you need to do is create a script on either your projectile or the zombie that contains the OnCollisionEnter function (make sure you declare it exactly like they do in the docs.) Then call the Destroy() function on the appropriate object.

This example would be within a script on the projectile:

 // Note: untested C# code
 private void OnCollisionEnter(Collision collision)
 {
      // You probably want a check here to make sure you're hitting a zombie
      // Note that this is not the best method for doing so.
      if ( collision.gameObject.name == "zombie" )
      {
           Destroy(collision.gameObject);
      }
 }

Reference This may likely be of some help as well. http://unity3d.com/support/documentation/ScriptReference/Collider.OnCollisionEnter.html

You can read more about various collider combinations (what will and will not call these scripts) here: http://unity3d.com/support/documentation/Components/class-MeshCollider.html

Hope this helps!

public GameObject Circle; public void oncollision(Collision col ){

 if (col.gameObject.name == "Circle")
         Destroy (this.gameObject);
     Debug.Log ("Destroyed");
 }

It does not work .How to solve this problem