I understand that it is possible for the event horizon of a black hole to support damped modes of vibration called quasi-normal modes, in which it oscillates between spherical and and various oblate shapes. I also understand that if we ignore shrinkage due to Hawking radiation, the area of the black hole's event horizon can never decrease. Does this mean that as the event horizon of a black hole oscillates, its surface area is constrained to remain constant (or at least non-decreasing) while it is oscillating?
Seems this is where action/reaction simply applies. Get a balloon and make an event horizon and play with it for awhile.