I'd like to extend that to ask whether there is something missing or not stated in the Riddle, whose absence is a clue. Admittedly this is drawing a rather long bow, but it's an idea. My thoughts drifted to the works of JRR Tolkien. The Orc, you will recall, is a particularly fierce creature that populates the darker regions of the stories. So it would be unwise to rule out a Tolkien connection.
Riddles occur in numbers in Tolkien's books, too, so the thought is again strengthened.
If you want to check the main ones, see the Hobbit Riddle Page . In the Land of Mordor where the Shadows lie. Let's compare them. Needless to say, neither of these respond to a Ping. This also draws a blank.