We study a composite millicharged dark matter model. The dark matter is in
the form of pion-like objects emerging from a higher scale QCD-like theory. We
present two distinct possibilities with interesting phenomenological
consequences based on the choice of the parameters. In the first one, the dark
matter is produced non-thermally and it could potentially account for the 130
GeV Fermi photon line via decays of the "dark pions". We estimate the
self-interaction cross section which might play an important role both in
changing the dark matter halo profile at the center of the galaxy and in making
the dark matter warmer. In the second version the dark matter is produced via
the freeze-in mechanism. Finally we impose all possible astrophysical,
cosmological and experimental constraints. We study in detail generic
constraints on millicharged dark matter that can arise from anomalous isotope
searches of different elements and we show why constraints based on direct
searches from underground detectors are not generally valid.Comment: 10 pages, published versio