  String theory compactification involves manifolds with multiple warp factors.
For cosmological applications, one often introduces a short, high-energy
inflationary throat, and a long,low-energy Standard Model throat. It is assumed
that at the end of inflation,the excited Kaluza-Klein modes from the
Inflationary throat tunnel to the SM throat and reheat Standard Model degrees
of freedom, which are attached to probe brane(s). However, the huge hierarchy
of energy scales can result in a highly dynamic transition of the throat
geometry. We point out that in such a cosmological scenario the Standard Model
throat (together with SM brane) will be cloaked by a Schwarzschild horizon,
produced by the Kaluza-Klein modes tunneling from the short throat. The Black
Brane formation is dual to the first order chiral phase transition of the
cascading gauge theory. We calculate the critical energy density corresponding
the formation of the the BH horizon in the long throat. We discuss the duality
between "Black Universe" cosmology and an expanding universe driven by the hot
gauge theory radiation. We address the new problem of the hierarchical
multiple-throat scenarios: SM brane disappearance after the decay of the BH
horizon.
