Spherically symmetric electrically counterpoised dust either collapses or disperses

We explore the dynamical evolution of spherically symmetric objects made of electrically counterpoised dust in general relativity. It has been claimed that these objects are in neutral equilibrium and, therefore, that black hole mimickers made of electrically counterpoised dust are feasible. Here we show that if a velocity is imparted to the fluid elements, no matter how small, the evolution leads either to a black hole or to the dispersion of the fluid. Furthermore, in the case of collapse, the resulting object is necessarily an extremal Reissner-Nordstr\"om black hole.