  The properties of the dark matter that determine its thermal relic abundance
can be very different from the dark matter properties today. We investigate
this possibility by coupling a dark matter sector to a scalar that undergoes a
phase transition after the dark matter freezes out. If the value of Omega_DM
h^2 calculated from parameters measured at colliders and by direct and indirect
detection experiments does not match the astrophysically observed value, a
novel cosmology of this type could provide the explanation. This mechanism also
has the potential to account for the "boost factor" required to explain the
PAMELA data.
