We study the high energy thermodynamics of little string theory, using its
holographic description. This leads to the entropy-energy relation S = beta
E-H + alpha log E + O(1/E). We compute alpha and show that it is negative;
as a consequence, the high energy thermodynamics is unstable. We exhibit a
mode localized near the horizon of the black brane, which has winding numb
er one around euclidean time and a mass that vanishes at large E (or beta -
-> beta (H)). We argue that the high temperature phase of the theory involv
es condensation of this mode.