  Recently it was conjectured that the strongly attractive antikaon--nucleon
potential can result in the formation of antikaon nuclear bound states. We
discuss the formation of such states as possible residues in heavy ion
collisions. In this context, we calculate the excitation functions of single-
and double-$K^-$ clusters in terms of the statistical thermal model. We show
that, if such objects indeed exist, then, in heavy ion collisions, the
single-$K^-$ clusters are most abundantly produced at present SIS energies,
while the double-$K^-$ clusters show a pronounced maximum yield in the energy
domain of the future accelerator at GSI. This is a direct consequence of: i)
the baryonic dominance in low energy heavy ion collisions and the large
baryonic content of the antikaonic bound states; ii) the strong energy
dependence of strangeness production at low energies.
  The production yields of double-strange clusters is compared with that of
double strange baryons. It is shown that at SIS energy there is a linear
scaling relation of the $\Xi^-/K^+$ with $K^+/p$ yields ratio.
