Anti-dark matter: a hidden face of mirror world

B and L violating interactions of ordinary particles with their twin particles from hypothetical mirror world can co-generate baryon asymmetries in both worlds in comparable amounts, $\Omega'_B/\Omega_B \sim 5$ or so. On the other hand, the same interactions induce the oscillation phenomena between the neutral particles of two sectors which convert e.g. mirror neutrons into our antineutrons. These oscillations are environment dependent and can have fascinating physical consequences.