  We study the dynamics of probe M5 branes with dissolved M2 charge in bubbling
geometries with SO(4) x SO(4) symmetry. These solutions were constructed by
Bena-Warner and Lin-Lunin-Maldacena and correspond to the vacua of the
maximally supersymmetric mass-deformed M2 brane theory. We find that
supersymmetric probe M2 branes polarize into M5 brane shells whose backreaction
creates an additional bubble in the geometry. We explicitly check that the
supersymmetric polarization potential agrees with the one found within the
Polchinski-Strassler approximation. The main result of this paper is that probe
M2 branes whose orientation is opposite to the background flux can polarize
into metastable M5 brane shells. These decay to a supersymmetric configuration
via brane-flux annihilation. Our findings suggest the existence of metastable
states in the mass-deformed M2 brane theory.
