NullObject

The NullObject is a special System Object that is used by the reap_delete and killobj utilities.

When you use the reap_delete and killobj utilities to purge Objects from the database, the affected Objects are converted to NullObjects. A NullObject is a place-holder in the parent Object’s History. It indicates that an Object that used to exist in the parent Container no longer exists.

The NullObject can be created anywhere in the database so the Containment Rules do not apply to the NullObject. Since the NullObject has no use or value in the hierarchy or on the Desktop there is no need to create the Object or to alter the Containment Rules; you cannot access the Can be Created By window (that is, the Containment Rules) in pcmadmin for the NullObject.