  The decay of a metastable false vacuum by bubble nucleation is studied in the
high temperature limit of the gauge theory in which an SO(3) gauge symmetry is
spontaneously broken to an SO(2). The effects of internal symmetry are so
drastic that, in addition to the known Euclidean bounce solution, there exists
a new bubble solution involving a 't Hooft-Polyakov monopole at its center the
moment it is nucleated. The decay rate and evolution are analyzed.
