Cannot implicitly convert type `UnityEngine.Object' to `UnityEngine.GameObject'. An explicit conversion exists (are you missing a cast?)

Questions & Answers
1

Does Anyone know why it says this?

using UnityEngine;
using System.Collections;

public class Shoot : MonoBehaviour {

public GameObject Projectile;

void Update(){
	if (Input.GetKeyDown (KeyCode.Space)) {
		GameObject Clone;
		Clone = Instantiate (Projectile, transform.position, transform.rotation);
		Rigidbody Force;
		Force = Clone.rigidbody;
		Force.AddForce (Vector3.forward * 100);
	}
}

}

2

Instantiate can create a copy of any UnityEngine.Object - so it returns UnityEngine.Object. You need to cast the result

    Clone = Instantiate(Projectile, transform.position, transform.rotation) as GameObject;