  The crisis of both cold and collisional dark matter (DM) models is resolved
by postulating flavor mixing of DM particles. Flavor-mixed particles segregate
in the gravitational field to form dark halos composed of heavy mass
eigenstates. Since these particles are mixed in the interaction basis, elastic
collisions convert some of heavy eigenstates into light ones which leave the
halo. This annihilation-like process will soften dense central cusps of halos.
The proposed model accumulates most of the attractive features of
self-interacting and annihilating DM models, but does not suffer from their
severe drawbacks. This model is natural does not require fine tuning.
