LazyngletonBehaviour.cs

using UnityEngine;

public class LazyngletonBehaviour<T> : MonoBehaviour where T : LazyngletonBehaviour<T> {

  private static T _instance;
  public static T Instance {
    get{
      if(_instance == null){
        GameObject newInstance = new GameObject();
        _instance = newInstance.AddComponent<T>();
        newInstance.name = _instance.GetType().Name;
        _instance.OnFirstCall();
      }
      return _instance;
    }
  }

  protected virtual void OnFirstCall () {}

}