Legosteroid.cs

using UnityEngine;
using System.Collections;

public class Legosteroid : MonoBehaviour {

    public GameObject legosteroid;
    public GameObject piece1;
    public GameObject piece2;
    public GameObject piece3;
    public GameObject piece4;

    public GameObject brick1;
    public GameObject brick2;
    public GameObject brick3;
    public GameObject brick4;

    void Awake()
    {

    }

    void OnCollisionEnter(Collision collision)
    {
        if (collision.gameObject.tag == "Bullet")
        {
            brick1 = (GameObject)Instantiate(piece1, new Vector3(gameObject.transform.position.x + 1, gameObject.transform.position.y - 2, 5), Quaternion.identity);
            brick2 = (GameObject)Instantiate(piece2, new Vector3(gameObject.transform.position.x - 2, gameObject.transform.position.y + 1, 5), Quaternion.identity); 
            brick3 = (GameObject)Instantiate(piece3, new Vector3(gameObject.transform.position.x - 1.4f, gameObject.transform.position.y + 2, 5), Quaternion.identity);
            brick4 = (GameObject)Instantiate(piece4, new Vector3(gameObject.transform.position.x + 3, gameObject.transform.position.y + 1, 5), Quaternion.identity);

            iTween.MoveTo(brick1, new Vector3(brick1.transform.position.x + 20, brick1.transform.position.y - 17, 5), 10);
            iTween.MoveTo(brick2, new Vector3(brick1.transform.position.x - 22, brick1.transform.position.y + 35, 5), 10);
            iTween.MoveTo(brick3, new Vector3(brick1.transform.position.x - 35, brick1.transform.position.y - 22, 5), 10);
            iTween.MoveTo(brick4, new Vector3(brick1.transform.position.x + 40, brick1.transform.position.y + 20, 5), 10);
            Destroy(gameObject);
        }
        if (brick1.transform.position.z != 5)
            brick1.transform.position = new Vector3(brick1.transform.position.x, brick1.transform.position.y, 5);
        if (brick2.transform.position.z != 5)
            brick2.transform.position = new Vector3(brick2.transform.position.x, brick2.transform.position.y, 5);
        if (brick3.transform.position.z != 5)
            brick3.transform.position = new Vector3(brick3.transform.position.x, brick3.transform.position.y, 5);
        if (brick4.transform.position.z != 5)
            brick4.transform.position = new Vector3(brick4.transform.position.x, brick4.transform.position.y, 5);
    }

    void Update()
    {
        gameObject.transform.eulerAngles = new Vector3(gameObject.transform.eulerAngles.x + 5, gameObject.transform.eulerAngles.y, gameObject.transform.eulerAngles.z);
    }
}