In a new empty project with a new scene:
- add a child game object to the default Directional Light in the scene
- create a new C# script and attach it to this object
- disable the Direction Light game object
- delete the script from the Project Browser

You now have an active gameobject with a missing reference to a script as a child to an inactive gameobject.

Go to Play Mode and Unity throws the following error: http://i.imgur.com/3HAQ9Ln.png then crashes. Couldn't reproduce with Unity 5.3.4p4