Conversion problem

Hello everyone,

I realise this question has probably been asked before, I did some digging myself and found some answers, however, they did not solve my problem, and the only answer that did, created a new one.

I'm trying to instantiate a particle system with lightning, I'm doing this the same way I did it in my last project (where I instantiated 2 laser beams). When I use (GameObject) Instantiate it gives me : InvalidCastException: Cannot cast from source type to destination type. TankActions.Update () (at Assets/TankActions.cs:26)

So I looked it up and it said to try Instantiate() as GameObject, which is what I did in the code example below. That worked, but if I try to access it afterwards, it tells me PlasmaBall is Null: NullReferenceException: Object reference not set to an instance of an object TankActions.Update () (at Assets/TankActions.cs:34)

I did make it work as a Transform instead of a gameobject, but then I ran into a problem when I tried to use Destroy. Anyone that knows why it's giving me this problem and what I should do about it?

public class TankActions : MonoBehaviour { public Transform PlasmaBallPrefab; public GameObject BarrelControl; private float chargeTime=1.0f; private float chargedTime=4.0f; private bool charging=false; private bool charged=false; private GameObject PlasmaBall; // Use this for initialization void Start () { //BarrelControl = GameObject.Find ("BarrelControl"); } // Update is called once per frame void Update () { if(Input.GetButtonDown("Jump")) { PlasmaBall = Instantiate(PlasmaBallPrefab, BarrelControl.transform.position+BarrelControl.transform.forward*2+BarrelControl.transform.up*0.4f, BarrelControl.transform.rotation*Quaternion.Euler (new Vector3(90,90,90))) as GameObject; PlasmaBall.rigidbody.AddForce(BarrelControl.transform.forward * 500); } } }