  Vacuum decay and symmetry breaking play an important role in the fundamental
structure of the matter and the evolution of the universe. In this work we
study how the purely classical effect of accretion of fundamental fields onto
black holes can lead to shells of symmetry restoration in the midst of a
symmetry broken phase. We also show how it can catalyze vacuum decay, forming a
bubble that expands asymptotically at the speed of light. These effects offer
an alternative, purely classical mechanism to quantum tunnelling for seeding
phase transitions in the universe.
