i challenge you to explain why this: 1: prints "What was null???" 2: throws an NRE 3: DOES NOT THROW IF YOU REMOVE ANY LINE IN mangler()

bad_csharp.cs

using System.Runtime.InteropServices;
using System.Reflection;
using System;

public class lol {
  internal delegate void lolwut();
  static Delegate d;
  static MethodInfo info;
  static unsafe byte* rawptr;
  public static void Main(System.String[] args) {
    info = typeof(lol).GetMethod("mangler");
    d = Delegate.CreateDelegate(typeof(lolwut), info);
    unsafe {
      rawptr = (byte*)Marshal.GetFunctionPointerForDelegate(d).ToPointer();
      *rawptr = 0x00;
    }
    try {
      mangler();
    } catch (NullReferenceException nre) {
      Console.WriteLine("What was null???");
    }
  }

  public static void mangler() {
    // note we don't even use the falue here! remove this, NRE stops
    Marshal.GetFunctionPointerForDelegate(d);
    // removing this stops the NRE
    d = Delegate.CreateDelegate(typeof(lolwut), info);
    // changing this to String.Format("{0}", "") stops the NRE. return value is unused!
    String.Format("{0:s}", "");
    unsafe {
      // remove this, NRE stops!
      Marshal.GetDelegateForFunctionPointer<lolwut>((IntPtr)rawptr)();
    }
  }
}