Super heavy thermal dark matter
  We propose a mechanism of elementary thermal dark matter with mass up to
$10^{14}$ GeV, within a standard cosmological history, whose relic abundance is
determined solely by its interactions with the Standard Model, without
violating the perturbative unitarity bound. The dark matter consists of many
nearly degenerate particles which scatter with the Standard Model bath in a
nearest-neighbor chain, and maintain chemical equilibrium with the Standard
Model bath by in-equilibrium decays and inverse decays. The phenomenology
includes super heavy elementary dark matter and heavy relics that decay at
various epochs in the cosmological history, with implications for CMB,
structure formation and cosmic ray experiments.
