Prevent a virtual method from being called from a it's singleton child class

namespace JurassicEra
{

	public abstract class Godzilla
	{
		public Godzilla()
		{
			// some unrelated logic 
		}

		protected virtual byte[] tickle(object feather , object water)
		{
			if(feather == null)
			{
				return null;
			}
			return this.ScratchFoot(feather, water);
		}
	}
}

namespace InstagramEra
{
	public sealed class Lizard : Godzilla
	
	private static Lizard instance;
	private static object syncRoot = new object();
	
	public static Lizard getInstance()
	{
	    if (instance == null)
		{
			lock (syncRoot)
			{
				if (instance == null)
				{
					instance = new Lizard();
				}
			}
		}
		return instance;
	}
	
	private Lizard()
	{
	}
	
	public void MakeHimLaugh(object feather , object water)
	{
		Theater theater = new Comedy();
		object poorLizard = this.tickle(feather, water);
		
		theater.startMovie();		
	}	
}

public void CheckIfMovieStarted()
{
	var fakeGodzilla = Isolate.Fake.AllInstances<Godzilla>();	
	Isolate.NonPublic.WhenCalled(fakeGodzilla, "tickle").WillReturn(null);	
}

public void CheckIfMovieStarted()
{
	Isolate.Invoke.StaticConstructor<Lizard>();
	var fakeLizard = Lizard.getInstance();	
	Isolate.NonPublic.WhenCalled(fakeLizard, "tickle").WillReturn(null);	
}

public void CheckIfMovieStarted()
{
	var fakeLizard = Lizard.getInstance();	
	Isolate.NonPublic.WhenCalled(fakeLizard, "tickle").WillReturn(null);	
}