Astonishingly, it is possible that a stable particle made of quarks exists, which has eluded detection:  the neutral, spin-0 state of 6 light quarks, uuddss, denoted S for sexaquark.  Unique among light 6-quark states, Fermi statistics allows quarks in this configuration to inhabit the spatially symmetric, lowest-energy wave-function.   Therefore it may be deeply enough bound that the m_S <  2054 MeV (m_p + m_e + m_Lambda).  If so, the S's lifetime is greater than the age of the Universe and it can be the Dark Matter.  The DM abundance can be calculated from known QCD parameters and is in agreement with the observed DM density within uncertainties.   So far, SDM is consistent with all known constraints.  This colloquium will explain the above in non-specialist accessible terms, including why Dark Matter direct detection experiments would not yet have seen SDM so far, and outline strategies for discovering the S in laboratory experiments.