  Quantum mechanics around black holes has shown to be one of the most
fascinating fields of theoretical physics. It involves both general relativity
and particle physics, opening new eras to establish the principles of unified
theories. In this article, we show that quantum bound states with no classical
equivalent -- as it can easily be seen at the dominant monopolar order --
should be formed around black holes for massive scalar particles. We
qualitatively investigate some important physical consequences, in particular
for the Hawking evaporation mechanism and the associated greybody factors.
