  Recent developments in bigravity allow one to construct consistent theories
of interacting spin-2 particles that are free of ghosts. In this framework, we
propose an elementary spin-2 dark matter candidate with a mass well below the
TeV scale. We show that, in a certain regime where the interactions induced by
the spin-2 fields do not lead to large departures from the predictions of
general relativity, such a light dark matter particle typically self-interacts
and undergoes self-annihilations via 3-to-2 processes. We discuss its
production mechanisms and also identify the regions of the parameter space
where self-interactions can alleviate the discrepancies at small scales between
the predictions of the collisionless dark matter paradigm and cosmological
N-body simulations.
