  We present a novel mechanism for generating both the baryon and dark matter
densities of the Universe. A new Dirac fermion X carrying a conserved baryon
number charge couples to the Standard Model quarks as well as a GeV-scale
hidden sector. CP-violating decays of X, produced non-thermally in
low-temperature reheating, sequester antibaryon number in the hidden sector,
thereby leaving a baryon excess in the visible sector. The antibaryonic hidden
states are stable dark matter. A spectacular signature of this mechanism is the
baryon-destroying inelastic scattering of dark matter that can annihilate
baryons at appreciable rates relevant for nucleon decay searches.
