  We show that dark matter emerging from late decays (z < 1000) produces a
linear power spectrum identical to that of Cold Dark Matter (CDM) on all
observationally relavant scales (> 0.1 Mpc), and simultaneously generates
observable constant-density cores in small dark matter halos. We refer to this
class of models as meta-Cold Dark Matter (mCDM), because it is born with
non-relativistic velocities from the decays of cold thermal relics. The
constant-density cores are a result of the low phase-space density of mCDM at
birth. Warm dark matter cannot produce similar size phase-space limited cores
without saturating the Ly-alpha power spectrum bounds. Dark matter dominated
galaxy rotation curves and stellar velocity dispersion profiles may provide the
best means to discriminate between mCDM and CDM. mCDM candidates are motivated
by the particle spectrum of supersymmetric and extra dimensional extensions to
the standard model of particle physics.
