#Unity3D

DontDestroyOnLoadController.cs

using UnityEngine;

public class DontDestroyOnLoadController<T> : MonoBehaviour where T : MonoBehaviour
{
    public static T Instance;

    private object _lock = new object();

    protected virtual void Awake()
    {
        lock (_lock)
        {
            Debug.Log(Instance);

            if (Instance != null)
            {
                Destroy(gameObject);
            }
            else
            {
                Instance = gameObject.GetComponent<T>();

                DontDestroyOnLoad(gameObject);
            }
        }
    }
}