In Greek mythology, the Sphinx crouched outside of Thebes, asking travelors a riddle and killing them if they failed to answer it, thus exemplifying the harsh reality that a priceless truth discovered a moment too late is worthless. Sphinx's evidently don't have eternity to wait for the right answer, nor are they particularly eager to have the riddle unraveled and undone. When Oedipus gave the right answer, the Sphinx of Thebes killed itself.
Strange, that, and very Sphinxlike, not to mention puzzling, until you realize that the Sphinx, like its riddle, cannot endure its unravelment, because it ceases to be mysterious, inscrutable, enigmatic or challenging. That is, it ceases to be what a a Sphinx must be: namely, Sphinxlike. The riddle unravled is a riddle no more. Riddles, however, being inherently suicidal, ask to be unraveled, so the Sphinx killed itself, not Oedipus, for such was its purpose, and such was its end.
Deadly though Sphinxs can be if veiled, riddles are not inherently homicidal, then. They are made to make us think, to think hard, and to understand that our life and well-being depends on seeing the the truth in time. Devoid of malice or mercy, the Sphinx confronts us with a conundrum that can make us or break us.
That said, consider this riddle: Whose eye's light is darkness, and how great is that darkness the further it sees? Here are some hints:
"Society is produced by our wants, government by our wickedness." -- Thomas Paine
"the light of a Master Mason is darkness visible" --Freemason and Rev. George Oliver, as quoted in "Blood On The Altar" by Craig Heimbichner, p 56