  In 2005 Sheldon Glashow has proposed his sinister model, opening the path to
composite-dark-matter scenarios, in which heavy stable electrically charged
particles bound in neutral atoms play the role of dark matter candidates.
Though the general problem of new stable single charged particles, forming with
ordinary electrons anomalous isotopes of hydrogen, turned out to be
unresolvable in Glashow's scenario, this scenario stimulated development of
composite dark matter models, which can avoid the trouble of anomalous isotope
overproduction. In the simplest case composite dark matter may consist of -2
charged particles, bound by ordinary Coulomb interaction with primordial helium
in OHe dark matter model. The advantage and open problems of this model are
discussed.
