codigo para objetos caigan sucesivamente sin apretar un boton

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Spawner : MonoBehaviour
{
    public GameObject[] obj;

    private int objIndex;

    public float timeLeft;
    public float timeBetween;

    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        if (timeLeft <= 0)
        {
            objIndex = Random.Range(0, obj.Length);

            Instantiate(obj[objIndex], transform.position, Quaternion.identity);

            timeLeft = timeBetween;
        }
        else
        {
            timeLeft -= Time.deltaTime;
        }
    }
}