  We propose a "scotogenic" mechanism relating small neutrino mass and
cosmological dark matter. Neutrinos are Dirac fermions with masses arising only
in two--loop order through the sector responsible for dark matter. Two triality
symmetries ensure both dark matter stability and strict lepton number
conservation at higher orders. A global spontaneously broken U(1) symmetry
leads to a physical $Diracon$ that induces invisible Higgs decays which add up
to the Higgs to dark matter mode. This enhances sensitivities to
spin-independent WIMP dark matter search below $m_h/2$.
