Bullet Prefab not instantiating

 var BulletPrefab:GameObject;
 var force : float = 2000;
  
 function OnGUI()
 {
         if (GUI.Button(Rect(250,350,75,75),"")) 
         {
             var bullet = Instantiate(BulletPrefab, 
              GameObject.Find("Player").transform.position, 
              GameObject.Find("Player").transform.rotation);
              bullet.rigidbody.AddForce(bullet.transform.forward * force);
          }
 }

I created a button that's supposed to instantiate and give a forward force to a bullet game object - but whenever I press it, the game object appears in the inspector but not actually on the game screen, can anybody tell me how to fix it?