  The paper discusses phenomena close to the critical QCD temperature, using
the holographic model. One issue studied is the overcooled high-T phase, in
which we calculate quasi normal sound modes. We do not find instabilities
associated with other first order phase transitions, but nevertheless observe
drastic changes in sound propagation/dissipation. The rest of the paper
considers a cluster of the high-T phase in the UV in coexistence with the low-T
phase, in a simplified ansatz in which the wall separating them is positioned
only in the holographic coordinate. This allows to find the force on the wall
and classical motion of the cluster. When classical motion is forbidden, we
evaluate tunneling probability through the remaining barrier.
