  We present a new paradigm of dark matter freeze-out, where the annihilation
of dark matter particles is catalyzed. We discuss in detail the regime that the
depletion of dark matter proceeds via $2\chi \to 2A'$ and $3A' \to 2\chi$
processes, in which $\chi$ and $A'$ denote dark matter and the catalyst
respectively. In this regime, the dark matter number density is depleted
polynomially rather than exponentially (Boltzmann suppression) as in classic
WIMPs and SIMPs. The paradigm applies for a secluded weakly interacting dark
sector with a dark matter in the $\text{MeV-TeV}$ mass range. The catalyzed
annihilation paradigm is compatible with CMB and BBN constraints, with enhanced
indirect detection signals.
